Disapearing buttons [bug?]

I’ve got a weird bit of behaviour on my pyrevit extension.
It’s been behaving properly for 2 years, but now recently I’ve gotten this issue where buttons, and sometimes entire panels are:

  1. Loaded
  2. Briefly show up visually
  3. Suddenly vanish
  4. Are useable through hotkeys.

I’ve managed to record the behaviour in this gif here. The following happens every time I reload.
Others have it with entire panels sometimes and I honestly do not know what is causing it.
I’ve managed to gather that there is some consistancy in which panel dissapears.
Most often it’s the “General” panel which probably has the most buttons in it. For me, only the ‘export’ button dissapears. Others have the entire general panel dissapear. If it were a “limitted amount of buttons” issue I’d expect this behaviour to be the same across the board… but it isn’t

I have around 80 pushbuttons buttons on my extension ribbon divided into several panels
THe extension is also split into our disciplines.
So I have a structure a little like this:

├─ stuff.tab/
│ ├─ general.panel/
├─ stuff.tab/
│ ├─ general.panel/
│ ├─ rooms.panel/
│ ├─ doors.panel/
├─ stuff.tab/
│ ├─ general.panel/
│ ├─ formwork.panel/
│ ├─ rebar.panel/
├─ stuff.tab/
│ ├─ general.panel/
│ ├─ hvac.panel/

Never seen this one
this could be the issue CreateRibbonTab

Autodesk.Revit.Exceptions.InvalidOperationException Too many custom tabs have been created in this session. (Maximum is 20).

but I would expect some kind of error message popping or in the journal file

I’ve managed to figure out what is causing the issue on my machine at least. A bit dumb (as is mostly the case)

In both my core and stru extensions, there was a folder called Export.pulldown
Shouldn;t be a problem for pyRevit, however the issue was that my stru’s pulldown bundle was completely empty.
The moment I added in a pushbutton with a script ( or deleted the pulldown folder) the pulldown apeared again.

I’m glad that got sorted out with a bit of investigating. But this does not seem to solve the case where the entire .panel is missing.

I’m going keep an eye on it and report back if I can find some more information. In the meantime I’m marking this as solved.