Patch for MMB on file upload

[Harri Porten]

Hi!

David reported that it is impossible to paste text into file upload 
elements with the middle-mouse button. Here is the result of my debugging 
session and a proposed fix.

The file upload element is different from other form elements because 
KUrlRequester is a composite of two QWidgets (a KLineEdit and a 
KPushButton). I found out that a MMB click does not have a symmetric event 
delivery. The mouse press event goes to the embedded KLineEdit but the 
release goes to the KUrlRequester. Hence the past within 
QPushButton::mouseReleaseEvent() is not triggered.

The asymmetry stems from RenderWidget::handleEvent() make the following 
exception for *left* mouse buttons on press

      if ( button == Qt::LeftButton )
         view()->setMouseEventsTarget( target );

but unconditionally using the result on release:

     target = view()->mouseEventsTarget();

My naive fix (attached) consists of doing this for the left button only:

     if ( button == Qt::LeftButton )
         target = view()->mouseEventsTarget();

Whether this is the real and full fix I don't know. Maybe we should be 
doing this for all buttons. Then there are differences between press and 
release when it comes to the target widget.

Harri.
-------------- next part --------------
Index: rendering/render_replaced.cpp
===================================================================
--- rendering/render_replaced.cpp	(revision 873041)
+++ rendering/render_replaced.cpp	(working copy)
@@ -1015,7 +1015,8 @@
             if ( button == Qt::LeftButton )
                 view()->setMouseEventsTarget( target );
         } else {
-            target = view()->mouseEventsTarget();
+            if ( button == Qt::LeftButton )
+                target = view()->mouseEventsTarget();
             if (target) {
                 QWidget * parent = target;
                 while (parent && parent != m_widget)