diff --git a/mail/base/content/SearchDialog.js b/mail/base/content/SearchDialog.js
index 277d88d4dd..49786d7f37 100644
--- a/mail/base/content/SearchDialog.js
+++ b/mail/base/content/SearchDialog.js
@@ -17,6 +17,9 @@ var { PluralForm } = ChromeUtils.importESModule(
 );
 var { TagUtils } = ChromeUtils.import("resource:///modules/TagUtils.jsm");
 
+var messenger;
+var msgWindow;
+
 var gCurrentFolder;
 
 var gFolderDisplay;
diff --git a/mail/base/content/SearchDialog.xhtml b/mail/base/content/SearchDialog.xhtml
index fba5f35ac2..69b97bf431 100644
--- a/mail/base/content/SearchDialog.xhtml
+++ b/mail/base/content/SearchDialog.xhtml
@@ -37,6 +37,7 @@
   <stringbundle id="bundle_messenger" src="chrome://messenger/locale/messenger.properties"/>
   <stringbundle id="bundle_brand" src="chrome://branding/locale/brand.properties"/>
 
+  <script src="chrome://messenger/content/commandglue.js"/>
   <script src="chrome://messenger/content/searchWidgets.js"/>
   <script src="chrome://messenger/content/mailWindow.js"/>
   <script src="chrome://messenger/content/folderDisplay.js"/>
diff --git a/mail/base/content/about3Pane.js b/mail/base/content/about3Pane.js
index dea65cf703..b5fe5edd71 100644
--- a/mail/base/content/about3Pane.js
+++ b/mail/base/content/about3Pane.js
@@ -664,7 +664,7 @@ var folderPaneContextMenu = {
         topChromeWindow.MsgOpenNewWindowForFolder(gFolder.URI, -1);
         break;
       case "folderPaneContext-searchMessages":
-        topChromeWindow.gFolderTreeController.searchMessages(gFolder);
+        commandController.doCommand("cmd_searchMessages");
         break;
       case "folderPaneContext-subscribe":
         topChromeWindow.MsgSubscribe(gFolder);
diff --git a/mail/base/content/folderPane.js b/mail/base/content/folderPane.js
index 23fb60391a..fe82750a52 100644
--- a/mail/base/content/folderPane.js
+++ b/mail/base/content/folderPane.js
@@ -409,17 +409,6 @@ var gFolderTreeController = {
     );
   },
 
-  /**
-   * Opens a search window with the given folder, or the selected one if none
-   * is given.
-   *
-   * @param [aFolder] the folder to open the search window for, if different
-   *                  from the selected one
-   */
-  searchMessages(aFolder) {
-    MsgSearchMessages(aFolder);
-  },
-
   /**
    * Prompts for confirmation, if the user hasn't already chosen the "don't ask
    * again" option.
diff --git a/mail/base/content/mailCommon.js b/mail/base/content/mailCommon.js
index e65ab36a84..f7c15369f1 100644
--- a/mail/base/content/mailCommon.js
+++ b/mail/base/content/mailCommon.js
@@ -286,6 +286,15 @@ var commandController = {
     cmd_space() {
       // TODO: Implement
     },
+    cmd_searchMessages() {
+      // We always open a new search dialog for each search command.
+      top.openDialog(
+        "chrome://messenger/content/SearchDialog.xhtml",
+        "_blank",
+        "chrome,resizable,status,centerscreen,dialog=no",
+        { folder: gFolder }
+      );
+    },
   },
   _isCallbackEnabled: {},
 
@@ -464,6 +473,9 @@ var commandController = {
       case "cmd_applyFilters": {
         return this._getViewCommandStatus(Ci.nsMsgViewCommandType.applyFilters);
       }
+      case "cmd_searchMessages": {
+        return true;
+      }
     }
 
     return false;
diff --git a/mail/base/content/mailWindowOverlay.js b/mail/base/content/mailWindowOverlay.js
index acf378a4c9..d6dac00190 100644
--- a/mail/base/content/mailWindowOverlay.js
+++ b/mail/base/content/mailWindowOverlay.js
@@ -2042,29 +2042,6 @@ function openGlodaSearchTab() {
   document.getElementById("tabmail").openTab("glodaFacet");
 }
 
-/**
- * Opens a search window with the given folder, or the displayed one if none is
- * chosen.
- *
- * @param {nsIMsgFolder} folder - The folder to open the search window for, if
- *   different from the displayed one.
- */
-function MsgSearchMessages(folder) {
-  // Don't trigger anything if there are no accounts configured. This is to
-  // disable potential triggers via shortcuts.
-  if (MailServices.accounts.accounts.length == 0) {
-    return;
-  }
-
-  // We always open a new search dialog for each search command
-  window.openDialog(
-    "chrome://messenger/content/SearchDialog.xhtml",
-    "_blank",
-    "chrome,resizable,status,centerscreen,dialog=no",
-    { folder }
-  );
-}
-
 function MsgSearchAddresses() {
   var args = { directory: null };
   OpenOrFocusWindow(
diff --git a/mail/base/content/mainCommandSet.inc.xhtml b/mail/base/content/mainCommandSet.inc.xhtml
index e5bf41b95e..4419c29a23 100644
--- a/mail/base/content/mainCommandSet.inc.xhtml
+++ b/mail/base/content/mainCommandSet.inc.xhtml
@@ -134,6 +134,7 @@
     <command id="cmd_findAgain" oncommand="goDoCommand('cmd_findAgain')" disabled="true"/>
     <command id="cmd_findPrevious" oncommand="goDoCommand('cmd_findPrevious')"
              disabled="true"/>
+    <command id="cmd_searchMessages" oncommand="goDoCommand('cmd_searchMessages');"/>
     <!-- Stop/abort current network activities. -->
     <command id="cmd_stop" oncommand="goDoCommand('cmd_stop')"/>
     <command id="cmd_reload" oncommand="goDoCommand('cmd_reload')"/>
diff --git a/mail/base/content/mainKeySet.inc.xhtml b/mail/base/content/mainKeySet.inc.xhtml
index 0ff36c9d5a..a07d6281ee 100644
--- a/mail/base/content/mainKeySet.inc.xhtml
+++ b/mail/base/content/mainKeySet.inc.xhtml
@@ -177,8 +177,8 @@
   <!-- Tools Keys -->
   <key id="key_searchMail"
        key="&searchMailCmd.key;"
-       oncommand="MsgSearchMessages();"
-       modifiers="accel,shift"/>
+       modifiers="accel,shift"
+       command="cmd_searchMessages"/>
   <key id="key_errorConsole"
        key="&errorConsoleCmd.commandkey;"
        oncommand="toJavaScriptConsole();"
diff --git a/mail/base/content/messenger-menubar.inc.xhtml b/mail/base/content/messenger-menubar.inc.xhtml
index 676060b9f3..02b58b41c3 100644
--- a/mail/base/content/messenger-menubar.inc.xhtml
+++ b/mail/base/content/messenger-menubar.inc.xhtml
@@ -281,7 +281,7 @@
         <menuitem id="searchMailCmd" label="&searchMailCmd.label;"
                   key="key_searchMail"
                   accesskey="&searchMailCmd.accesskey;"
-                  oncommand="MsgSearchMessages();"/>
+                  command="cmd_searchMessages"/>
         <menuitem id="glodaSearchCmd"
                   label="&glodaSearchCmd.label;"
                   accesskey="&glodaSearchCmd.accesskey;"
diff --git a/mail/components/customizableui/content/panelUI.inc.xhtml b/mail/components/customizableui/content/panelUI.inc.xhtml
index 9872df156c..95afcf4907 100644
--- a/mail/components/customizableui/content/panelUI.inc.xhtml
+++ b/mail/components/customizableui/content/panelUI.inc.xhtml
@@ -509,7 +509,7 @@
                        class="subviewbutton subviewbutton-iconic"
                        data-l10n-id="appmenu-tools-message-search"
                        key="key_searchMail"
-                       oncommand="MsgSearchMessages();"/>
+                       command="cmd_searchMessages"/>
         <toolbarbutton id="appmenu_filtersCmd"
                        class="subviewbutton subviewbutton-iconic"
                        data-l10n-id="appmenu-tools-message-filters"
diff --git a/mail/test/browser/folder-display/browser_rightClickMiddleClickFolders.js b/mail/test/browser/folder-display/browser_rightClickMiddleClickFolders.js
index a40728b77e..e4a541dab7 100644
--- a/mail/test/browser/folder-display/browser_rightClickMiddleClickFolders.js
+++ b/mail/test/browser/folder-display/browser_rightClickMiddleClickFolders.js
@@ -14,7 +14,6 @@ var {
   assert_folder_selected,
   assert_folder_selected_and_displayed,
   assert_folders_selected_and_displayed,
-  assert_no_folders_selected,
   assert_selected_tab,
   be_in_folder,
   close_popup,
@@ -26,7 +25,6 @@ var {
   reset_context_menu_background_tabs,
   right_click_on_folder,
   select_click_folder,
-  select_no_folders,
   select_shift_click_folder,
   set_context_menu_background_tabs,
   switch_tab,
@@ -49,27 +47,6 @@ add_setup(async function() {
   await make_message_sets_in_folders([folderC], [{ count: 1 }]);
 });
 
-/**
- * Make sure that a right-click when there is nothing currently selected does
- *  not cause us to display something, as well as correctly causing a transient
- *  selection to occur.
- */
-add_task(async function test_right_click_folder_with_nothing_selected() {
-  // This should cause folderA to be displayed
-  await be_in_folder(folderA);
-
-  select_no_folders();
-  assert_no_folders_selected();
-
-  await right_click_on_folder(folderB);
-  assert_folder_selected(folderB);
-  // The displayed folder shouldn't change
-  assert_folder_displayed(folderA);
-
-  await close_popup(mc, getFoldersContext());
-  assert_no_folders_selected();
-}).skip();
-
 /**
  * One-thing selected, right-click on something else.
  */
@@ -130,33 +107,6 @@ add_task(async function test_right_click_folder_on_existing_multi_selection() {
   assert_folders_selected_and_displayed(folderB, folderC);
 }).skip();
 
-/**
- * Middle clicking should open a message in a tab, but not affect our selection.
- */
-async function _middle_click_folder_with_nothing_selected_helper(aBackground) {
-  // This should cause folderA to be displayed
-  await be_in_folder(folderA);
-
-  select_no_folders();
-  assert_no_folders_selected();
-
-  let originalTab = mc.tabmail.currentTabInfo;
-  let [newTab] = middle_click_on_folder(folderA);
-  if (aBackground) {
-    // Make sure we haven't switched to the new tab.
-    assert_selected_tab(originalTab);
-    // Now switch to the new tab and check
-    await switch_tab(newTab);
-  }
-  assert_folder_selected_and_displayed(folderA);
-  close_tab(newTab);
-
-  // XXX This is wrong, we shouldn't have anything selected. Since we don't
-  // have a special state for nothing selected, we're giving this a pass for
-  // now.
-  assert_folder_selected_and_displayed(folderA);
-}
-
 /**
  * One-thing selected, middle-click on something else.
  */
diff --git a/mail/test/browser/folder-tree-modes/browser_modeSwitching.js b/mail/test/browser/folder-tree-modes/browser_modeSwitching.js
index 8810d3da75..acc0120187 100644
--- a/mail/test/browser/folder-tree-modes/browser_modeSwitching.js
+++ b/mail/test/browser/folder-tree-modes/browser_modeSwitching.js
@@ -13,7 +13,6 @@ var {
   inboxFolder,
   make_message_sets_in_folders,
   mc,
-  select_no_folders,
   toggle_main_menu,
 } = ChromeUtils.import(
   "resource://testing-common/mozmill/FolderDisplayHelpers.jsm"
@@ -64,8 +63,6 @@ add_setup(async function() {
 
   tree = mc.folderTreeView;
 
-  select_no_folders();
-
   // Main menu is needed for this whole test file.
   menu_state = toggle_main_menu(true);
 
diff --git a/mail/test/browser/search-window/browser.ini b/mail/test/browser/search-window/browser.ini
index 734d56b7c5..d2a69cdb55 100644
--- a/mail/test/browser/search-window/browser.ini
+++ b/mail/test/browser/search-window/browser.ini
@@ -7,9 +7,9 @@ prefs =
   mailnews.start_page.url=about:blank
   datareporting.policy.dataSubmissionPolicyBypassNotification=true
 subsuite = thunderbird
-skip-if = true # TODO
 
 [browser_multipleSearchWindows.js]
 [browser_rightClickToOpenSearchWindow.js]
 [browser_searchWindow.js]
 [browser_searchFromSyntheticView.js]
+skip-if = true # TODO
diff --git a/mail/test/browser/search-window/browser_multipleSearchWindows.js b/mail/test/browser/search-window/browser_multipleSearchWindows.js
index b9199636e7..4ba1311ff6 100644
--- a/mail/test/browser/search-window/browser_multipleSearchWindows.js
+++ b/mail/test/browser/search-window/browser_multipleSearchWindows.js
@@ -73,19 +73,5 @@ add_task(
     // Clean up, close both windows
     close_search_window(swc1);
     close_search_window(swc2);
-
-    Assert.report(
-      false,
-      undefined,
-      undefined,
-      "Test ran to completion successfully"
-    );
   }
 );
-
-registerCleanupFunction(() => {
-  // Some tests that open new windows don't return focus to the main window
-  // in a way that satisfies mochitest, and the test times out.
-  Services.focus.focusedWindow = window;
-  window.gFolderDisplay.tree.focus();
-});
diff --git a/mail/test/browser/search-window/browser_rightClickToOpenSearchWindow.js b/mail/test/browser/search-window/browser_rightClickToOpenSearchWindow.js
index cde91c3dbe..651066f12e 100644
--- a/mail/test/browser/search-window/browser_rightClickToOpenSearchWindow.js
+++ b/mail/test/browser/search-window/browser_rightClickToOpenSearchWindow.js
@@ -6,12 +6,9 @@
 
 var {
   assert_folders_selected_and_displayed,
-  assert_no_folders_selected,
   create_folder,
   enter_folder,
   select_click_folder,
-  select_no_folders,
-  show_folder_pane,
 } = ChromeUtils.import(
   "resource://testing-common/mozmill/FolderDisplayHelpers.jsm"
 );
@@ -26,26 +23,10 @@ var {
 
 var folderA, folderB;
 add_setup(async function() {
-  show_folder_pane();
   folderA = await create_folder("RightClickToOpenSearchWindowA");
   folderB = await create_folder("RightClickToOpenSearchWindowB");
 });
 
-/**
- * Test opening a search window while nothing is selected.
- */
-add_task(async function test_open_search_window_with_nothing_selected() {
-  // Make sure the folders we need are visible
-  await enter_folder(folderB);
-  select_no_folders();
-  assert_no_folders_selected();
-
-  let swc = await open_search_window_from_context_menu(folderA);
-  assert_search_window_folder_displayed(swc, folderA);
-
-  close_search_window(swc);
-});
-
 /**
  * Test opening a search window while the same folder is selected.
  */
diff --git a/mail/test/browser/search-window/browser_searchFromSyntheticView.js b/mail/test/browser/search-window/browser_searchFromSyntheticView.js
index e59c6b1dd6..9eb099eb3d 100644
--- a/mail/test/browser/search-window/browser_searchFromSyntheticView.js
+++ b/mail/test/browser/search-window/browser_searchFromSyntheticView.js
@@ -10,6 +10,7 @@ const {
   create_folder,
   create_thread,
   delete_messages,
+  get_about_3pane,
   inboxFolder,
 } = ChromeUtils.import(
   "resource://testing-common/mozmill/FolderDisplayHelpers.jsm"
@@ -60,7 +61,7 @@ add_task(async function testSearchDialogFolderSelectedFromSyntheticView() {
     GlodaMsgIndexer.indexFolder(folder, { callback, force: true });
   });
 
-  let dbView = window.gFolderDisplay.view.dbView;
+  let dbView = get_about_3pane().gDBView;
   await TestUtils.waitForCondition(
     () =>
       thread.synMessages.every((_, i) =>
diff --git a/mail/test/browser/search-window/browser_searchWindow.js b/mail/test/browser/search-window/browser_searchWindow.js
index b0bce8f3e4..d225ee59e1 100644
--- a/mail/test/browser/search-window/browser_searchWindow.js
+++ b/mail/test/browser/search-window/browser_searchWindow.js
@@ -25,8 +25,6 @@ var {
   open_selected_messages,
   plan_for_message_display,
   reset_open_message_behavior,
-  select_click_row,
-  select_shift_click_row,
   set_open_message_behavior,
   switch_tab,
   wait_for_all_messages_to_load,
@@ -37,6 +35,9 @@ var {
 var {
   assert_search_window_folder_displayed,
   open_search_window,
+  assert_messages_in_search_view,
+  select_click_search_row,
+  select_shift_click_search_row,
 } = ChromeUtils.import(
   "resource://testing-common/mozmill/SearchWindowHelpers.jsm"
 );
@@ -45,11 +46,10 @@ var {
   async_plan_for_new_window,
   plan_for_window_close,
   wait_for_modal_dialog,
-  wait_for_new_window,
   wait_for_window_close,
 } = ChromeUtils.import("resource://testing-common/mozmill/WindowHelpers.jsm");
 
-var folder, setFoo, setBar, setFooBar;
+var folder, setFooBar;
 
 // Number of messages to open for multi-message tests
 var NUM_MESSAGES_TO_OPEN = 5;
@@ -59,7 +59,7 @@ var NUM_MESSAGES_TO_OPEN = 5;
  */
 add_task(async function test_create_messages() {
   folder = await create_folder("SearchWindowA");
-  [setFoo, setBar, setFooBar] = await make_message_sets_in_folders(
+  [, , setFooBar] = await make_message_sets_in_folders(
     [folder],
     [{ subject: "foo" }, { subject: "bar" }, { subject: "foo bar" }]
   );
@@ -135,7 +135,7 @@ add_task(function test_go_search() {
   wait_for_all_messages_to_load(swc);
 
   // - Verify we got the right messages
-  assert_messages_in_view(setFooBar, swc);
+  assert_messages_in_search_view(setFooBar, swc);
 
   // - Click the "Save as Search Folder" button, id "saveAsVFButton"
   // This will create a virtual folder properties dialog...
@@ -160,7 +160,7 @@ add_task(async function test_open_single_search_result_in_tab() {
 
   // Select one message
   swc.e("threadTree").focus();
-  let msgHdr = select_click_row(1, swc);
+  let msgHdr = select_click_search_row(1, swc);
   // Open the selected message
   open_selected_message(swc);
   // This is going to trigger a message display in the main 3pane window
@@ -169,7 +169,7 @@ add_task(async function test_open_single_search_result_in_tab() {
   assert_number_of_tabs_open(preCount + 1);
   // Check that the currently displayed tab is a message tab (i.e. our newly
   // opened tab is in the foreground)
-  assert_tab_mode_name(null, "message");
+  assert_tab_mode_name(null, "mailMessageTab");
   // Check that the message header displayed is the right one
   assert_selected_and_displayed(msgHdr);
   // Clean up, close the tab
@@ -189,8 +189,11 @@ add_task(async function test_open_multiple_search_results_in_new_tabs() {
 
   // Select a bunch of messages
   swc.e("threadTree").focus();
-  select_click_row(1, swc);
-  let selectedMessages = select_shift_click_row(NUM_MESSAGES_TO_OPEN, swc);
+  select_click_search_row(1, swc);
+  let selectedMessages = select_shift_click_search_row(
+    NUM_MESSAGES_TO_OPEN,
+    swc
+  );
   // Open them
   open_selected_messages(swc);
   // This is going to trigger a message display in the main 3pane window
@@ -199,7 +202,7 @@ add_task(async function test_open_multiple_search_results_in_new_tabs() {
   assert_number_of_tabs_open(preCount + NUM_MESSAGES_TO_OPEN);
   // Check that the currently displayed tab is a message tab (i.e. one of our
   // newly opened tabs is in the foreground)
-  assert_tab_mode_name(null, "message");
+  assert_tab_mode_name(null, "mailMessageTab");
 
   // Now check whether each of the NUM_MESSAGES_TO_OPEN tabs has the correct
   // title
@@ -229,7 +232,7 @@ add_task(async function test_open_search_result_in_new_window() {
 
   // Select a message
   swc.e("threadTree").focus();
-  let msgHdr = select_click_row(1, swc);
+  let msgHdr = select_click_search_row(1, swc);
 
   let newWindowPromise = async_plan_for_new_window("mail:messageWindow");
   // Open it
@@ -252,14 +255,14 @@ add_task(async function test_open_search_result_in_existing_window() {
 
   // Open up a window
   swc.e("threadTree").focus();
-  select_click_row(1, swc);
+  select_click_search_row(1, swc);
   let newWindowPromise = async_plan_for_new_window("mail:messageWindow");
   open_selected_message(swc);
   let msgc = await newWindowPromise;
   wait_for_message_display_completion(msgc, true);
 
   // Select another message and open it
-  let msgHdr = select_click_row(2, swc);
+  let msgHdr = select_click_search_row(2, swc);
   plan_for_message_display(msgc);
   open_selected_message(swc);
   wait_for_message_display_completion(msgc, true);
diff --git a/mail/test/browser/shared-modules/FolderDisplayHelpers.jsm b/mail/test/browser/shared-modules/FolderDisplayHelpers.jsm
index 8da533ecbc..b19e3488d1 100644
--- a/mail/test/browser/shared-modules/FolderDisplayHelpers.jsm
+++ b/mail/test/browser/shared-modules/FolderDisplayHelpers.jsm
@@ -38,7 +38,6 @@ const EXPORTED_SYMBOLS = [
   "assert_messages_not_in_view",
   "assert_messages_summarized",
   "assert_multimessage_pane_focused",
-  "assert_no_folders_selected",
   "assert_not_selected_tab",
   "assert_not_showing_unread_only",
   "assert_not_shown",
@@ -123,7 +122,6 @@ const EXPORTED_SYMBOLS = [
   "select_click_row",
   "select_column_click_row",
   "select_control_click_row",
-  "select_no_folders",
   "select_none",
   "select_shift_click_folder",
   "select_shift_click_row",
@@ -1439,17 +1437,6 @@ function assert_folder_expanded(aFolder) {
   }
 }
 
-/**
- * Clear the selection in the folder tree view.
- */
-function select_no_folders() {
-  wait_for_message_display_completion();
-  mc.folderTreeView.selection.clearSelection();
-  mark_action("fdh", "select_no_folder", []);
-  // give the event queue a chance to drain...
-  mc.sleep(0);
-}
-
 /**
  * Pretend we are clicking on a folder with our mouse.
  *
@@ -2249,7 +2236,7 @@ function assert_selected(...aArgs) {
   let [troller, desiredIndices] = _process_row_message_arguments(...aArgs);
 
   // - get the actual selection (already sorted by integer value)
-  let selectedIndices = get_about_3pane_or_about_message().gDBView.getIndicesForSelection();
+  let selectedIndices = get_db_view(troller.window).getIndicesForSelection();
 
   // - test selection equivalence
   // which is the same as string equivalence in this case. muah hah hah.
@@ -2946,7 +2933,6 @@ function assert_folders_selected_and_displayed(...aArgs) {
   }
 }
 
-var assert_no_folders_selected = assert_folders_selected_and_displayed;
 var assert_folder_selected_and_displayed = assert_folders_selected_and_displayed;
 
 /**
diff --git a/mail/test/browser/shared-modules/SearchWindowHelpers.jsm b/mail/test/browser/shared-modules/SearchWindowHelpers.jsm
index c33cc0ef9b..dfac18ca14 100644
--- a/mail/test/browser/shared-modules/SearchWindowHelpers.jsm
+++ b/mail/test/browser/shared-modules/SearchWindowHelpers.jsm
@@ -5,24 +5,29 @@
 "use strict";
 
 const EXPORTED_SYMBOLS = [
+  "assert_messages_in_search_view",
+  "assert_search_window_folder_displayed",
+  "close_search_window",
   "open_search_window",
   "open_search_window_from_context_menu",
-  "close_search_window",
-  "assert_search_window_folder_displayed",
+  "select_click_search_row",
+  "select_shift_click_search_row",
 ];
 
-var folderDisplayHelper = ChromeUtils.import(
+var { get_about_3pane, mc, right_click_on_folder } = ChromeUtils.import(
   "resource://testing-common/mozmill/FolderDisplayHelpers.jsm"
 );
 var windowHelper = ChromeUtils.import(
   "resource://testing-common/mozmill/WindowHelpers.jsm"
 );
+
+var { Assert } = ChromeUtils.importESModule(
+  "resource://testing-common/Assert.sys.mjs"
+);
 var EventUtils = ChromeUtils.import(
   "resource://testing-common/mozmill/EventUtils.jsm"
 );
 
-var mc = folderDisplayHelper.mc;
-
 /**
  * Open a search window using the accel-shift-f shortcut.
  *
@@ -42,15 +47,14 @@ function open_search_window() {
  * @returns the controller for the search window
  */
 async function open_search_window_from_context_menu(aFolder) {
-  await folderDisplayHelper.right_click_on_folder(aFolder);
+  let win = get_about_3pane();
+  let context = win.document.getElementById("folderPaneContext");
+  let item = win.document.getElementById("folderPaneContext-searchMessages");
+  await right_click_on_folder(aFolder);
 
   windowHelper.plan_for_new_window("mailnews:search");
-  mc.folderTreeController.searchMessages();
-  let swc = windowHelper.wait_for_new_window("mailnews:search");
-
-  await folderDisplayHelper.close_popup(mc, mc.e("folderPaneContext"));
-
-  return swc;
+  context.activateItem(item);
+  return windowHelper.wait_for_new_window("mailnews:search");
 }
 
 /**
@@ -66,12 +70,134 @@ function close_search_window(aController) {
  */
 function assert_search_window_folder_displayed(aController, aFolder) {
   let currentFolder = aController.currentFolder;
-  if (currentFolder != aFolder) {
-    throw new Error(
-      "The search window's selected folder should have been: " +
-        aFolder.prettyName +
-        ", but is actually: " +
-        currentFolder.prettyName
+  Assert.equal(
+    currentFolder,
+    aFolder,
+    "The search window's selected folder should have been: " +
+      aFolder.prettyName +
+      ", but is actually: " +
+      currentFolder?.prettyName
+  );
+}
+
+/**
+ * Pretend we are clicking on a row with our mouse.
+ *
+ * @param {number} aViewIndex - The view index to click.
+ * @param {MozMillController} aController - The controller in whose context to
+ *   do this.
+ * @returns {nsIMsgDBHdr} The message header selected.
+ */
+function select_click_search_row(aViewIndex, aController) {
+  if (aController == null) {
+    aController = mc;
+  }
+
+  let tree = aController.threadTree;
+  let coords = tree.getCoordsForCellItem(
+    aViewIndex,
+    tree.columns.subjectCol,
+    "cell"
+  );
+  let treeChildren = tree.lastElementChild;
+  EventUtils.synthesizeMouse(
+    treeChildren,
+    coords.x + coords.width / 2,
+    coords.y + coords.height / 2,
+    {},
+    aController.window
+  );
+
+  return aController.dbView.getMsgHdrAt(aViewIndex);
+}
+
+/**
+ * Pretend we are clicking on a row with our mouse with the shift key pressed,
+ * adding all the messages between the shift pivot and the shift selected row.
+ *
+ * @param {number} aViewIndex - The view index to click.
+ * @param {MozMillController} aController The controller in whose context to
+ *   do this.
+ * @returns {nsIMsgDBHdr[]} The message headers for all messages that are now
+ *   selected.
+ */
+function select_shift_click_search_row(aViewIndex, aController) {
+  if (aController == null) {
+    aController = mc;
+  }
+
+  let tree = aController.threadTree;
+  let coords = tree.getCoordsForCellItem(
+    aViewIndex,
+    tree.columns.subjectCol,
+    "cell"
+  );
+  let treeChildren = tree.lastElementChild;
+  EventUtils.synthesizeMouse(
+    treeChildren,
+    coords.x + coords.width / 2,
+    coords.y + coords.height / 2,
+    { shiftKey: true },
+    aController.window
+  );
+
+  aController.sleep(0);
+  return aController.folderDisplay.selectedMessages;
+}
+
+/**
+ * Assert that the given synthetic message sets are present in the folder
+ * display.
+ *
+ * Verify that the messages in the provided SyntheticMessageSets are the only
+ * visible messages in the provided DBViewWrapper.
+ *
+ * @param {SyntheticMessageSet} aSynSets - Either a single SyntheticMessageSet
+ *   or a list of them.
+ * @param {MozMillController} aController - The controller which we get the
+ *   folderDisplay property from.
+ */
+function assert_messages_in_search_view(aSynSets, aController) {
+  if (aController == null) {
+    aController = mc;
+  }
+  if (!Array.isArray(aSynSets)) {
+    aSynSets = [aSynSets];
+  }
+
+  // Iterate over all the message sets, retrieving the message header.  Use
+  // this to construct a URI to populate a dictionary mapping.
+  let synMessageURIs = {}; // map URI to message header
+  for (let messageSet of aSynSets) {
+    for (let msgHdr of messageSet.msgHdrs()) {
+      synMessageURIs[msgHdr.folder.getUriForMsg(msgHdr)] = msgHdr;
+    }
+  }
+
+  // Iterate over the contents of the view, nulling out values in
+  // synMessageURIs for found messages, and exploding for missing ones.
+  let dbView = aController.folderDisplay.view.dbView;
+  let treeView = aController.folderDisplay.view.dbView.QueryInterface(
+    Ci.nsITreeView
+  );
+  let rowCount = treeView.rowCount;
+
+  for (let iViewIndex = 0; iViewIndex < rowCount; iViewIndex++) {
+    let msgHdr = dbView.getMsgHdrAt(iViewIndex);
+    let uri = msgHdr.folder.getUriForMsg(msgHdr);
+    Assert.ok(
+      uri in synMessageURIs,
+      "The view should show the message header" + msgHdr.messageKey
+    );
+    delete synMessageURIs[uri];
+  }
+
+  // Iterate over our URI set and make sure every message was shown.
+  for (let uri in synMessageURIs) {
+    let msgHdr = synMessageURIs[uri];
+    Assert.ok(
+      false,
+      "The view is should include the message header" + msgHdr.messageKey
     );
   }
 }