when a tooltip is open, opening a new one to replace it creates a white flash

[ix0rai]

tested on 4646bbd
video showing the issue:

you can see that on displaying the third tooltip, it flashes a white, incorrectly sized version before showing the correct tooltip.

[supersaiyansubtlety]

It happens twice:

Frame 65	Frame 81

You can also see part of "Decompiling" here:

Frame 130	(duplicate for consistent size)

The dimensions of the tooltip in each frame are (roughly):

Frame	Dimensions
65	325x133
81	325x133
130	325x90

So it seems like it's some default size before it decompiles and re-packs.

[supersaiyansubtlety]

I can't reproduce this on develop/2.8, but I've added some additional repainting in #346 to fix some artifacting; it might affect this, too.