Strange shadow-like behavior with GTK applications

[jEsuSdA 8)]

El 22/10/19 a las 21:26, Matt Connell escribió:
> I am getting some strange window behavior with certain desktop applications.  Attached is a screenshot of evince, as an example of what I am seeing.
> 
> Is this a window shadow related behavior?  Is there a setting in the compositor that I need to tweak?  Is this related to the discussion on client-side decorations?

Yes, it is.

In CSD windows, the "window" appearance falls on the window itself, no 
Window Decorator is involved.

So, in this case, the window border, header and shadows are from the 
Window instead of being painted by the window manager.

As some compositors can paint "shadows" around the windows, the result 
is we have two shadows: the compositor one and the CSD shadow.

There are two possible solutions:

1 - Disable CSD if you can: With gtk3-nocsd or launching apps with 
GTK_CSD=0 (if possible. Not working with all apps).

In this case, the Window Manager manages the window borders, so 
everything will works as expected.

2 - Maintain CSD and tune the compositor configuration (if possible. 
XFWM does not provide so much "fantasy" here).
In this case, the compositor shadow could be disabled, but CSD and 
non-CSD windows surely will not have the same appearance and behaviour. 
If you want having a better integration you have to tweaks your CSS GTK+ 
Theme files.

This is we are talking about in the CSD thread. ;)


Cheers! ;)