Clicking on 'Font Name Selector' dropdown list makes fonts disappear from Windows system

Using the latest beta (12). Windows 10 latest updates.

If I click on the font name selector dropdown list in the Format Toolbar, the dropdown list will show the names of the fonts, but only for a split of a second - it then goes completely empty and seems to freeze up and have a semi transparent look for another second, before it comes back again, but now only shows the TT (TrueType) icons to the left and no font names. Either its completely empty or just shows a few garbled pixels instead of the names.

After that, Scrivener will act up in all sorts of weird behaviors. Only some characters will show up in the editor while typing, for instance. Text will not be visible in Composition mode unless I set text scale to 100% (Even the dropdown list for changing text scale will only show options like 00%, 10%, 12%, 100% and 00% again)

Tabbing out to Windows Explorer will now have all text gone from folders and files. Only icons show up. And lots of other weird behaviors (involving missing or scrambled text).

Restarting the computer makes everything go back to normal again.

If I don’t touch the Font Name Selector dropdown list, I can still change and see all the fonts in Scrivener by right-clicking/Fonts/Show Fonts and it will display all the fonts properly (difference is that this list does not present the fonts with the TT icons and samples in the list, so I guess that is why it is working?)

I have uninstalled and reinstalled Scrivener. No difference.

What could be wrong?

An educated guess is update your graphics card driver, including the OpenGL driver.

By using right-click/Fonts/Show Fonts and then going through the whole list of fonts by selecting each one and having it display a sample in the little box, I found that I had three fonts (or font groups actually) that would not display correctly in the sample box.

Clicking on these fonts also caused the font-disappearing havoc in Windows Explorer etc.

If I remember correctly the three font groups were named

Source Code Variable
Source Serif Variable
Source Sans variable

I deleted these in Windows Explorer from the C:\Windows\Fonts folder.

After restarting the computer the dropdown list of fonts is displaying correctly in Scrivener again and no weird font missing scenarios. Yay!

However, before I deleted these font groups, I quickly tried them in other text and image applications and they were working fine without any hiccups. Only Scrivener (tested on both v1.9.9 and v3 Beta) was unable to handle them.

With the next update we upgrade to Qt 5.12.1. In the change list of the Qt library I notice that they have applied some font fixes and even fixed loading font crashes. Please, give the next Beta another try(when it is out) with these fonts and let us know how it works. Glad you have managed to pinpoint the fonts causing the problem.

Will the new version of QT also fix the pen tablet issue I reported in another thread?

I did not notice something explicitly written about the pen or tablet, unfortunately. Still it does not mean it has not changed. Most of the changes are one line sentences which are not very clear. I deeply hope Qt has addressed it.