Clicking on any tile in the NTP would hide the window. Surprising!...

third_party/mozilla/include/ToolTip.mm

 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
 /* ***** BEGIN LICENSE BLOCK *****
  * Version: MPL 1.1/GPL 2.0/LGPL 2.1
  *
  * The contents of this file are subject to the Mozilla Public License Version
  * 1.1 (the "License"); you may not use this file except in compliance with
  * the License. You may obtain a copy of the License at
  * http://www.mozilla.org/MPL/
  *
  * Software distributed under the License is distributed on an "AS IS" basis,
@@ skipping 47 matching lines @@
   {
     // the ref from -alloc is balanced by the -release in dealloc
     mTooltipWindow = [[NSWindow alloc] initWithContentRect:NSMakeRect(0.0, 0.0, kMaxTextFieldWidth, 0.0)
                                          styleMask:NSBorderlessWindowMask
                                            backing:NSBackingStoreBuffered
                                              defer:YES];
 
     // we don't want closing the window to release it, because we aren't always in control
     // of the close (AppKit may do it on quit).
     [mTooltipWindow setReleasedWhenClosed:NO];
-    
+
     // Create a textfield as the content of our new window.
     // Field occupies all but the top 2 and bottom 2 pixels of the panel (bug 149635)
     mTextView = [[NSTextView alloc] initWithFrame:NSMakeRect(0.0, kBorderPadding, kMaxTextFieldWidth, 0.0)];
     [[mTooltipWindow contentView] addSubview:mTextView];
     [mTextView release]; // window holds ref
-    
+
     // set up the panel
     [mTooltipWindow setHasShadow:YES];
     [mTooltipWindow setBackgroundColor:[NSColor colorWithCalibratedRed:1.0 green:1.0 blue:0.81 alpha:1.0]];
-    
+
 
     // set up the text view
     [mTextView setDrawsBackground:NO];
     [mTextView setEditable:NO];
     [mTextView setSelectable:NO];
     [mTextView setFont:[NSFont toolTipsFontOfSize:[NSFont smallSystemFontSize]]];
     [mTextView setMinSize:NSMakeSize(0.0, 0.0)];
     [mTextView setHorizontallyResizable:YES];
     [mTextView setVerticallyResizable:YES];
   }
   return self;
 }
 
 - (void)dealloc
 {
+  [self closeToolTip];
+
   [[NSNotificationCenter defaultCenter] removeObserver:self];
 
   [mTooltipWindow close];   // we set the window not to release on -close
   [mTooltipWindow release];
 
   [super dealloc];
 }
 
 - (void)showToolTipAtPoint:(NSPoint)windowPoint
                 withString:(NSString*)string
@@ skipping 26 matching lines @@
   [mTextView setFrame:NSMakeRect(0, kBorderPadding, 0, 0)];
 
   // -sizeToFit sucks. For some reason it likes to wrap short words, so
   // we measure the text by hand and set that as the min width.
   NSSize stringSize = [string sizeWithAttributes:[NSDictionary dictionaryWithObject:[NSFont toolTipsFontOfSize:[NSFont smallSystemFontSize]] forKey:NSFontAttributeName]];
   float textViewWidth = ceil(stringSize.width);
   if (textViewWidth > kMaxTextFieldWidth)
     textViewWidth = kMaxTextFieldWidth;
 
   textViewWidth += 2.0 * 5.0;   // magic numbers required to make the text not wrap. No, this isn't -textContainerInset.
-  
+
   // set up the text view
   [mTextView setMaxSize:NSMakeSize(kMaxTextFieldWidth, screenSize.height - 2 * kBorderPadding)]; // do this here since we know screen size
-  [mTextView setString:string]; // do this after setting max size, before setting constrained frame size, 
+  [mTextView setString:string]; // do this after setting max size, before setting constrained frame size,
                                 // reset to max width - it will not grow horizontally when resizing, only vertically
   [mTextView setConstrainedFrameSize:NSMakeSize(kMaxTextFieldWidth, 0.0)];
   // to avoid wrapping when we don't want it, set the min width
   [mTextView setMinSize:NSMakeSize(textViewWidth, 0.0)];
 
   // finally, do the buggy sizeToFit
   [mTextView sizeToFit];
   // The first time we sizeToFit a text field on Leopard, it decides that
   // 0 would be a good height. We disagree, so make it try again.
   NSRect textViewFrame = [mTextView frame];
   if (textViewFrame.size.height < 1.0) {
     [mTextView sizeToFit];
     textViewFrame = [mTextView frame];
   }
-  
+
   // set the origin back where its supposed to be
   [mTextView setFrameOrigin:NSMakePoint(0, kBorderPadding)];
-  
+
   // size the panel correctly, taking border into account
   NSSize textSize = textViewFrame.size;
   textSize.height += kBorderPadding + kBorderPadding;
   [mTooltipWindow setContentSize:textSize];
-  
+
   // We try to put the top left point right below the cursor. If that doesn't fit
   // on screen, put the bottom left point above the cursor.
   if (point.y - kVOffset - textSize.height > NSMinY(screenFrame)) {
     point.y -= kVOffset;
     [mTooltipWindow setFrameTopLeftPoint:point];
   }
   else {
     point.y += kVOffset / 2.5;
     [mTooltipWindow setFrameOrigin:point];
   }
-  
+
   // if it doesn't fit on screen horizontally, adjust so that it does
   float amountOffScreenX = NSMaxX(screenFrame) - NSMaxX([mTooltipWindow frame]);
   if (amountOffScreenX < 0) {
     NSRect movedFrame = [mTooltipWindow frame];
     movedFrame.origin.x += amountOffScreenX;
     [mTooltipWindow setFrame:movedFrame display:NO];
   }
 
-  // add as a child window    
+  // add as a child window
   [inWindow addChildWindow:mTooltipWindow ordered:NSWindowAbove];
   // show the panel
   [mTooltipWindow orderFront:nil];
 }
 
 - (void)closeToolTip
 {
   // we can get -closeToolTip even if we didn't show it
   if ([mTooltipWindow isVisible])
   {
     [[mTooltipWindow parentWindow] removeChildWindow:mTooltipWindow];
     [mTooltipWindow orderOut:nil];
   }
 
   [[NSNotificationCenter defaultCenter] removeObserver:self];
 }
 
 - (void)parentWindowDidResignKey:(NSNotification*)inNotification
 {
   [self closeToolTip];
 }
 
 @end