Bug 1867532 - Scroll selected row into view when opening thread pane context menu by keyboard. r=freaktechnik

Differential Revision: https://phabricator.services.mozilla.com/D195104

--HG--
extra : amend_source : 807182ccdea7437575006e8e6a403850559fcc1f

mail/base/content/about3Pane.js

@@ -4635,7 +4635,10 @@ var threadPane = {
   },
 
   _onItemActivate(event) {
-    if (gDBView.getFlagsAt(threadTree.selectedIndex) & MSG_VIEW_FLAG_DUMMY) {
+    if (
+      threadTree.selectedIndex < 0 ||
+      gDBView.getFlagsAt(threadTree.selectedIndex) & MSG_VIEW_FLAG_DUMMY
+    ) {
       return;
     }
 
@@ -4863,14 +4866,19 @@ var threadPane = {
       event.target.closest(`tr[is^="thread-"]`) ||
       threadTree.getRowAtIndex(threadTree.currentIndex);
     const isMouse = event.button == 2;
-    if (!isMouse && !row) {
+    if (!isMouse) {
+      if (threadTree.selectedIndex < 0) {
+        return;
+      }
       // Scroll selected row we're triggering the context menu for into view.
       threadTree.scrollToIndex(threadTree.currentIndex, true);
-      row = threadTree.getRowAtIndex(threadTree.currentIndex);
-      // Try again once in the next frame.
-      if (!row && !retry) {
-        window.requestAnimationFrame(() => this._onContextMenu(event, true));
-        return;
+      if (!row) {
+        row = threadTree.getRowAtIndex(threadTree.currentIndex);
+        // Try again once in the next frame.
+        if (!row && !retry) {
+          window.requestAnimationFrame(() => this._onContextMenu(event, true));
+          return;
+        }
       }
     }
     if (!row || gDBView.getFlagsAt(row.index) & MSG_VIEW_FLAG_DUMMY) {

mail/base/test/browser/browser_mailContext.js

@@ -411,12 +411,44 @@ add_task(async function testSingleMessage() {
   );
   mailContext.hidePopup();
 
+  // Open the menu through the keyboard on a message that is scrolled slightly
+  // out of view.
+
+  threadTree.selectedIndex = 5;
+  threadTree.scrollToIndex(threadTree.getLastVisibleIndex() + 7, true);
+  await new Promise(resolve => window.requestAnimationFrame(resolve));
+  Assert.equal(threadTree.currentIndex, 5, "Row 5 is the current row");
+  Assert.ok(row.parentNode, "Row element should still be attached");
+  Assert.greater(
+    threadTree.getFirstVisibleIndex(),
+    5,
+    "Selected row should no longer be visible"
+  );
+  EventUtils.synthesizeMouseAtCenter(
+    threadTree,
+    { type: "contextmenu", button: 0 },
+    about3Pane
+  );
+  await new Promise(resolve => window.requestAnimationFrame(resolve));
+  await BrowserTestUtils.waitForPopupEvent(mailContext, "shown");
+  Assert.greaterOrEqual(
+    5,
+    threadTree.getFirstVisibleIndex(),
+    "Current row is greater than or equal to first visible index"
+  );
+  Assert.lessOrEqual(
+    5,
+    threadTree.getLastVisibleIndex(),
+    "Current row is less than or equal to last visible index"
+  );
+  mailContext.hidePopup();
+
   // Open the menu on a message that is scrolled out of view.
 
   threadTree.scrollToIndex(200, true);
   await new Promise(resolve => window.requestAnimationFrame(resolve));
   Assert.ok(!row.parentNode, "Row element should no longer be attached");
-  Assert.equal(threadTree.currentIndex, 0, "Row 0 is the current row");
+  Assert.equal(threadTree.currentIndex, 5, "Row 5 is the current row");
   Assert.ok(
     !threadTree.getRowAtIndex(threadTree.currentIndex),
     "Current row is scrolled out of view"
@@ -431,6 +463,16 @@ add_task(async function testSingleMessage() {
     threadTree.getRowAtIndex(threadTree.currentIndex),
     "Current row is scrolled into view when showing context menu"
   );
+  Assert.greaterOrEqual(
+    5,
+    threadTree.getFirstVisibleIndex(),
+    "Current row is greater than or equal to first visible index"
+  );
+  Assert.lessOrEqual(
+    5,
+    threadTree.getLastVisibleIndex(),
+    "Current row is less than or equal to last visible index"
+  );
   mailContext.hidePopup();
 
   Assert.ok(BrowserTestUtils.is_hidden(mailContext), "Context menu is hidden");