fix for bug #44823.

when not in threaded mode, don't take up space for the twisty in the
subject column.  thanks to neil@parkwaycc.co.uk for the fix.
r=varga, sr=sspitzer

layout/xul/base/src/tree/src/nsTreeColFrame.cpp

@@ -191,7 +191,7 @@ nsTreeColFrame::AttributeChanged(nsIPresContext* aPresContext,
     EnsureTree();
     if (mTree)
       mTree->Invalidate();
-  } else if (aAttribute == nsXULAtoms::ordinal) {
+  } else if (aAttribute == nsXULAtoms::ordinal || aAttribute == nsXULAtoms::primary) {
     InvalidateColumnCache(aPresContext);
   }
 

mailnews/base/resources/content/searchBar.js

@@ -208,8 +208,8 @@ function restorePreSearchView()
     if (sortType != gDBView.sortType || sortOrder != gDBView.sortOrder)
     {
       gDBView.sort(sortType, sortOrder);
-      UpdateSortIndicators(sortType, sortOrder);
     }
+    UpdateSortIndicators(sortType, sortOrder);
 
     gPreQuickSearchView = null;    
   }

mailnews/base/resources/content/threadPane.js

@@ -258,12 +258,22 @@ function MsgSortDescending()
 
 function UpdateSortIndicators(sortType, sortOrder)
 {
-  var colID = ConvertSortTypeToColumnID(sortType);
-  var sortedColumn;
+  // show the twisties if the view is threaded
+  var currCol = document.getElementById("subjectCol");
+  var primary = (sortType == nsMsgViewSortType.byThread) && gDBView.supportsThreading;
+  currCol.setAttribute("primary", primary);
+
+  // remove the sort indicator from all the columns
+  currCol = document.getElementById("threadCol");
+  while (currCol) {
+    currCol.removeAttribute("sortDirection");
+    currCol = currCol.nextSibling;
+  }
 
   // set the sort indicator on the column we are sorted by
+  var colID = ConvertSortTypeToColumnID(sortType);
   if (colID) {
-    sortedColumn = document.getElementById(colID);
+    var sortedColumn = document.getElementById(colID);
     if (sortedColumn) {
       if (sortOrder == nsMsgViewSortOrder.ascending) {
         sortedColumn.setAttribute("sortDirection","ascending");
@@ -271,15 +281,6 @@ function UpdateSortIndicators(sortType, sortOrder)
       else {
         sortedColumn.setAttribute("sortDirection","descending");
       }
-
-      // remove the sort indicator from all the columns
-      // except the one we are sorted by
-      var currCol = sortedColumn.parentNode.firstChild;
-      while (currCol) {
-        if (currCol != sortedColumn && currCol.localName == "treecol")
-          currCol.removeAttribute("sortDirection");
-        currCol = currCol.nextSibling;
-      }
     }
   }
 }

mailnews/base/resources/content/threadPane.xul

@@ -36,7 +36,7 @@ Rights Reserved.
     onselect="ThreadPaneSelectionChanged();">
   <treecols>
     <treecol id="threadCol" display="&threadColumn.label;" class="treecol-image threadColumnHeader" currentView="unthreaded" cycler="true" persist="hidden ordinal" fixed="true" />
-    <treecol id="subjectCol" class="sortDirectionIndicator" persist="hidden ordinal width" flex="7" label="&subjectColumn.label;" primary="true"/>
+    <treecol id="subjectCol" class="sortDirectionIndicator" persist="hidden ordinal width" flex="7" label="&subjectColumn.label;" ignoreincolumnpicker="true"/>
     <splitter class="tree-splitter"/>
     <treecol id="senderOrRecipientCol" class="sortDirectionIndicator" persist="hidden ordinal width"  flex="4" label="&senderColumn.label;"/>
     <splitter class="tree-splitter"/>