Can someone please help me to fix a problem I have with XFCE on an Aspire One with a 1024x600 sized screen?

As you can see on this screenshot, the window is too big and cannot be scrolled/resized.
Auto-hiding or resizing the "taskbar" at the bottom is no help.
Note that chromium or GIMP behave perfectly and match my screen size automatically, this issue seems to occur only with certain windows like parameters settings.
This is a fresh install of LMDE with XFCE with native screen resolution set.
Thank you for reading and please forgive my bad english.


