What is causing Custom Panel icons to disappear ?

[D.T. Nethery]

From time to time I notice that on some of my custom panels the icons are blank. What causes this to happen ? Why don't the icons load properly ?
(The only fix seems to be to reinstall the custom panel , if it has been backed up; fortunately most of mine are backed up, but it is tedious to have to
reinstall the panel.)

Examples -

Custom Panel color palette (all the colors are gone)

Screen Shot 2023-05-30 at 9.52.17 AM.png (13.25 KiB) Viewed 1434 times

Custom Tool panel - Only a single eraser icon shows , but the other icons are blank

Screen Shot 2023-05-30 at 9.53.09 AM.png (29.49 KiB) Viewed 1434 times

[D.T. Nethery]

In another topic Thierry wrote:

We've already started to replace a lot of DIP images used in the software by PNGs (like icons for example), and this we'll likely do another pass for the next major version.

So I'm wondering now if this the reason that I'm noticing icons in Custom Panels disappearing in the the newer 11.7.1 version , because the icons used in my older custom panels were .DIP files , but have been replaced as PNGs ? (therefore the Custom Panel cannot find the original icons which were in .DIP format).

[Thierry]

This is something that has been bothering me for years, I have seen this happen several times, but never found a way to reproduce it :/

So I'm wondering now if this the reason that I'm noticing icons in Custom Panels disappearing in the the newer 11.7.1 version , because the icons used in my older custom panels were .DIP files , but have been replaced as PNGs ? (therefore the Custom Panel cannot find the original icons which were in .DIP format).

I don't think that's the case.
When we changed most of the icons from DIP to PNG in v11.7.0, we made it so the software could also read DIP files when it can't find the PNGs.
Besides, if my memory serves me right, the custom panels icons are still in the DIP format for now.