Version:            (using KDE Devel)
Installed from:    Compiled sources
OS:                Linux

The "Rename dialog" use a KPushButton for the "cancel" button. When the dialog is resized, the "cancel" button is resized too.

I've found on the kpushbutton.cpp file this code:
  setSizePolicy( QSizePolicy( QSizePolicy::Minimum, QSizePolicy::Minimum ) );

I've changed it to:
  setSizePolicy( QSizePolicy( QSizePolicy::Fixed, QSizePolicy::Fixed ) );
(Same as removing the setSizePolicy line)

In this way the button is not resized, but the dialog window is less clear. See the screenshot for an example.

The KPushButton should use the "Fixed" QSizePolicy and in the rename dialog it should be added a vertical spacer.