Strange problem with SLADE -- Graphics disappearing

[⇛Marnetmar⇛]

I have been having an issue with SLADE that started out as something I could work around, but lately, has become unbearable.

 

This just started happening one day out of the blue. Seemingly at random and with no rhyme or reason, graphics in WAD files will not show up. This can range from a few to swaths of dozens of them at at time. This happens in every wad I test this on, including IWADs. Here is an example from Doom.wad:

 

 

Not only do the affected graphics not show up in the entry browser, they don't show up in any other dialog either. Here's an example from the "new texture from patch" dialog:

 

 

Make no mistake, the WAD files are perfectly fine and un-corrupted, and the data is still there. Here's one of many textures from a collab I'm doing that's not showing up in SLADE:

 

 

As you can see, it shows up in Doom Builder (also in game but I can't be assed to take another screeshot) just fine:

 

 

To complicate matters further, any new graphics added to a wad with slade are automatically made invisible. They can be converted and manipulated and they will show up in game just fine, you just can't see them in SLADE while you're working with them.

 

I've tried deleting my SLADE installation and doing a fresh install multiple times but the exact same thing keeps happening. What the fuck is going on?