Pop-up chrome....

chrome/browser/cocoa/browser_window_controller.mm

Index: chrome/browser/cocoa/browser_window_controller.mm
===================================================================
--- chrome/browser/cocoa/browser_window_controller.mm	(revision 19669)
+++ chrome/browser/cocoa/browser_window_controller.mm	(working copy)
@@ -422,6 +422,11 @@
     return NO;
   }
 
+  // Can't drag a tab from a normal browser to a pop-up
+  if (browser_->type() != realSource->browser_->type()) {
+    return NO;
+  }
+
   return YES;
 }
 
@@ -684,6 +689,13 @@
   return base::SysUTF16ToNSString(contents->GetTitle());
 }
 
+// TYPE_POPUP is not normal (e.g. no tab strip)
+- (BOOL)isNormalWindow {
+  if (browser_->type() == Browser::TYPE_NORMAL)
+    return YES;
+  return NO;
+}
+
 - (void)selectTabWithContents:(TabContents*)newContents
              previousContents:(TabContents*)oldContents
                       atIndex:(NSInteger)index