So I've chosen a font by
System Settings -> Application Appearance -> Fonts
And there I've adjusted all fonts to be of 14th size. And also checked "Use my KDE fonts..." in Gtk+ appearance. I've also did the same using
kdesudo systemsettings
But still some fonts are tiny! It's not the 14th size!
Edit 2:
I thought it might be one of Gnome font settings. So I've increased all fonts in
gnome-tweak-tool
sudo gnome-tweak-tool
gconf-editor
sudo gconf-editor
No help!
Edit:
Ubuntu tweak also gives no help (note the tiny fonts!):
Edit:
It looks like the problem is with gtk3: when I compile emacs 24.0.92 with gtk3 - i get small menu fonts. When I do the same with a default gtk2 - everything is all right.
Unfortunately this is a known bug in KDE, where the font size of the shutdown dialogue is not affected by system settings. Please vote for the bug on the bug tracker if you would like it fixed.
https://bugs.kde.org/show_bug.cgi?id=211501
The problem is resolved by installing
from here.