Taskbar window icons disappear after color depth / resolution change

Using : reactos-bootcd-0.4.15-dev-4937-g6c748ca-x86-gcc-lin-dbg

"first" (see note below) window icon disappears from task bar after color depth / resolution change

Not systematic but got multiple occurences (after fresh boot on clean install)

Note on "first" : 

If display + Power + System are opened => display is affected, Power is OK, System is OK

If Display gets closed => power is affected, system is OK

If Power gets closed => system is affected

Also affects regular exe (not only control panel) :

Does not revert to correct display if settings are set again to their original values. Closing / reopening the "last" window keeps incorrect display upon reopening