andre_debian@numericable.fr composed on 2015-08-16 23:40 (UTC+0200):
Yes, the mouse works fine on another Linux Wheezy, with kde-trinity 3.5 : I can resize the windows.
What is it you are using now, Jessie?
How to reinstall kde -trinity 3.5 ? Which commands ? I think that it is not properly installed...
Maybe it's not Trinity but the driver not (properly) installed. Do you have both xserver-xorg-input-evdev and xserver-xorg-input-mouse installed? Maybe the solution is to force a switch from the one in use (according to Xorg.0.log) to the other. Jessie is probably using evdev as here, Wheezy more likely mouse.