LUIFormattedLabel causes LUI to visually glitch if text is continuously modified during runtime

[Nel-Fie]

As the title describes: if a LUIFormattedLabel has its text content continuously modified, as with a task calling .clear(), .add(str) and .newline() every tick, it will cause LUI to glitch out visually after some time.

Here is a file reproducing the glitch, at least on my system. LUI starts to glitch out at around 530 frames for me.

I had already touched on the issue over at the Panda3D forums, and rdb suggested it might have something to do with the text atlas running out of space.