I don't understand what you're meaning. Could you grab a screenshot?

CC: (none) => jani.valimaa

Created attachment 1687 [details]
Screenshot

Here is the screenshot for midori.
But I just seen there is the same problem for pavucontrol.
It seems it is a general problem.
I use LXDE.

Maybe some theming problem!?

Could you test some other theme? Preferably one which supports both GTK2 and GTK3, like Adwaita (install pkgs adwaita-gtk2-theme and adwaita-gtk3-theme).

I cannot change theme because lxappearance is crashing when I click on a theme.

[jacques@localhost ~]$ lxappearance
Gtk-Message: Failed to load module "canberra-gtk-module"
Erreur de segmentation (core dumped)
[jacques@localhost ~]$

If I install libcanberra-gtk0 I have :

[jacques@localhost ~]$ lxappearance
Erreur de segmentation (core dumped)
[jacques@localhost ~]$ 

but it continue crashing when I click on a theme.

If I use gtk-chtheme it crashes :

[jacques@localhost ~]$ gtk-chtheme

GLib-CRITICAL **: g_scanner_input_file: assertion `input_fd >= 0' failed
Erreur de segmentation (core dumped)
[jacques@localhost ~]$

the problem of window exists also with mail-notification.

Now, all is OK.

Closing as WORKSFORME.

Status: NEW => RESOLVED
Resolution: (none) => WORKSFORME