SCUMM/HE: Blue's Treasure Hunt - Missing Backgrounds during some animations

[Thunderforge]

This ticket was split off from #12505, posted by @cheatfreak47

I went ahead and went over my own copy of Blue's Clues: Blue's Treasure Hunt with a fine-toothed comb in the latest daily build ScummVM (at the time: windows-x86-64-master-cb14f43e), copying the files as instructed by the Wiki page and hunted for problems and came up with only a few.

Attached I will post some more or less completed savegames to try and assist with dev, but I don't know how useful they will be.

Worth noting that the actual game does work on modern Windows 10 with no issues, and can be windowed for comparison to scummVM.

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During sequences where Steve "Skidoos" into subareas, a background fails to render for some reason during a part of the animation. This also happens during/after the "found all 3 clues!" sequence, where steve is supposed to be shown sitting on his chair.
​​https://i.imgur.com/KfJR2yI.png
​​https://i.imgur.com/ImxKjQ0.png

[AndywinXp]

Hi, is this one still a thing?