New tree widget. r=saari, bug#30511

mailnews/compose/resources/content/addressingWidgetOverlay.js

@@ -201,8 +201,11 @@ function awNotAnEmptyArea(event)
 	event.preventBubble();
 }
 
-function awClickEmptySpace(setFocus)
+function awClickEmptySpace(targ, setFocus)
 {
+  if (targ.localName != 'treechildren')
+    return;
+
 	dump("awClickEmptySpace\n");
 	var lastInput = awGetInputElement(top.MAX_RECIPIENTS);
 

mailnews/compose/resources/content/addressingWidgetOverlay.xul

@@ -35,12 +35,16 @@ Rights Reserved.
 			<tree id="addressingWidgetTree"		
 				  class="addressingWidget"
 				  rows="3"
-				  onclick="awClickEmptySpace(true)"
+				  onclick="awClickEmptySpace(event.target, true)"
 				  ondragover="return DragOverTree(event);"
 				  ondragdrop="return DropOnAddressingWidgetTree(event);"
-				  style="width:0px;height:0px;border:solid black 1px">
+				  style="border:solid black 1px">
 				  
-				<treechildren id="addressWidgetBody">
+        <treecols>
+          <treecol flex="1"/>
+        </treecols>
+
+				<treechildren flex="1" id="addressWidgetBody">
 					<treeitem>
 						<treerow>
 							<treecell allowevents="true">