Pointer recenters itself in the dialogs

Hi, since a couple of months ago, I am unable to use the mouse in the dialogs:
First the pointer centers in the dialog(as intended?) but when I move the mouse to say select a file, it recenters automatically again and again making impossible to use the mouse there. Absolute pointer devices like a Wacom are not "so" afected by this behavior and one could operate in the dialogs with them.

It happens with both versions, the one available in Debian Sid(unstable) and the latest git selfcompiled. I've only reproduced this behavior with fvwm, the default window manager from Gnome performs right in the dialogs, not tested other wm.

Some thouts:
the default version provided in Sid worked fine previously and has this problem now without it being updated
some libraries had been updated, i don't know which ones could affect in this problem.
When I start the Gnome session and wm, which do not show this problem, the used dialogs seem to be the standard Gnome ones.

Any hints to debug?

Thanks
Pere

Some advance on this matter:
The problem has nothing to do with LibreCAD, later on I found it appearing in other apps too.
I had fvwm disabling autoraise of popup windows but positioning the cursor on them, for some strange reason the mouse got  repositioned again and again.
Commenting out the WarpToWindow line in ./fvwm/config fixes this problem.

DestroyFunc EWMHActivateWindowFunc
AddToFunc EWMHActivateWindowFunc I Iconify Off
+ I Focus
+ I WarpToWindow 50 50

Sorry for the noise
Pere