0.96.1 64bits: Scaling up default Ubuntu font excessively

[fractl]

XnView: MP 0.96.1 - 64 bit
OS: Linux (Ubuntu) - 64bit

New install of XNView MP (20 April 2020) suddenly scales up the font on all menus and toolbars

Effect: Long folder and file names are difficult to read.

To reproduce:
1. Install new XNView MP version (0.96.1) on Ubuntu 18.04 (LTS)

Actual behaviour (bug): XNView MP fonts of new version suddenly scale to large and unusable size - see screenshot and compare XNView menu / tree font with size of the image caption and window text
(I presume it used to use the system default zoom setting and now it's scaling up for some reason?)

Expected behaviour: Font size would stay as it always has been.

[xnview]

which version do you had before?

[fractl]

Hmm, I thought I was coming from 0.94.3, but not I'm not so sure. I was testing different versions after some issues with 0.94.3 that we resolved, but perhaps I left it on 0.92. Can't be sure.

Anyway, just deleted my user config folder, and reinstalled 0.92 - everything looks fine:

The install 0.94.3 - and the font has gone mad again. This has me a little stumped. I'm sure I've had 0.94.3 installed before without this problem.

I've tried several iterations, back and forth, with and without the config files (I thought perhaps something in the INI was causing this), but I can't seem to get past 0.92 now. I find that giant font really hard to live with - file and folder names are just too long these days.

[xnview]

do you have tried qtconfig?

[fractl]

What should I be trying with qtconfig? (I've not played with that before.)

[xnview]

you can change font settings used by Qt app

[fractl]

Okay, installed qtconfig-qt4. Fiddled around with the font size and themes. Restarted a bunch of times, and still... No.

What change would have caused this?

[xnview]

What change would have caused this?

0.92 uses Qt 5.9.5, 0.94 uses Qt 5.9.7, and 0.96 uses Qt 5.12.6, they have perhaps changed the default font size....

[fractl]

0.92 uses Qt 5.9.5, 0.94 uses Qt 5.9.7, and 0.96 uses Qt 5.12.6, they have perhaps changed the default font size....

Hmm, okay. I don't really know what to do with that unfortunately. Although I am surprised that I'm the only Ubuntu user with this problem. I'm going to have to stick with 0.92 and its smaller annoyance of the Upgrade reminder dialog for a bit because I can't live in giant font land.