Icon size in Okular and other applications

[solitone]

On Friday, 17 March 2017 11:26:39 CET solitone wrote:
> It's not just menu item icons in Okular. For instance, also the Save and
> Cancel icons in the Okular open document popup are small (attachment
> 1.jpeg), as well as the Save and Cancel icons in the Save File KDialog I
> get when saving something from Chrome (2.jpeg). By contrast, when saving a
> file from KWrite those two icons have a regular size (3.jpeg)

I've just noticed that in my system (debian GNU/linux stretch) kdialog and 
okular are based on an older Qt version:

solitone at alan:~$ kdialog --version
Qt: 4.8.7
KDE Development Platform: 4.14.26
KDialog: 1.0
solitone at alan:~$ okular --version
Qt: 4.8.7
KDE Development Platform: 4.14.26
Okular: 0.26.1

While kate and kmail, for example, that don't have the issue, are based on Qt 
5.7.1 and KDE Frameworks 5.28.0.

So the problem seems related to the version of Qt, where perhaps HiDPI support 
on version 4.8.x wasn't so mature?

Cheers,
  Davide