Better now, sprite is refreshed on stage and in corral, thumbnail after switch to script/sounds tab.
hmm... thanks! This uses OffscreenCanvas now. It's funny, because with OffscreenCanvas I'm now losing graphics data on my Mac, haha! Oh well, I'll just revert those changes for now, no use trying to fix an actual browser bug inside an application.
Works for me too
what if you make a sprite say a picture of something, like a ringed block. Then switch to another tab and back again. For me, the graphics inside the speech bubble then turn gray-ish, which also shouldn't happen with OffscreenCanvasses. Google are really great at breaking graphics 
# Issue 1294505: Canvas get cleared at page being invisible if experimental features is enabled
Seems to be already corrected for
++Corrections
Not-Reproducible on
100.0.4868.0- Canary
100.0.4867.0- Dev
99.0.4844.15- Beta
Requested to be backported to v98
Self-Merge-Request-98
Here's the result of my tests with google chrome and brave. I'm just testing to see if the costume turns into this
| browser/chromium version/snap version | with Accelerated 2D canvas | without Accelerated 2D canvas |
|---|---|---|
| Brave (chromium 98.0.4758.87) / snap 7.1.5 -dev | doesn't work | doesn't work |
| Google chrome (chromium 98.0.4758.102) / snap 7.1.5 -dev | doesn't work | doesn't work |
| Brave (chromium 98.0.4758.87) / snap 7.1.4 | works | works |
| Google chrome (chromium 98.0.4758.102) / snap 1.1.4 | works | works |
In conclusion, the current version doesn't have an issue, but the dev version does.
Strange but for me Google Chrome 98.0.4758.102 and Snap! 7.1.4 with Accelerated 2D canvas doesn't work (original problem where entire page is white until I interact with it and costume is gone)
It does not work on my PC.
Costumes of sprites, as well as the base Turtle sprite disappear.
Code displaying SAY msgs do work and display the message without the sprite visible.
Any combo of HIDE / SHOW does not change anything. Sprites / costumes still not visible.
# Issue 1294505: Canvas get cleared at page being invisible if experimental features is enabled
# Issue 1294863: Images drawn using canvas.drawImage method disappear after switching tabs
Accordingly to the bugs.chromium.org it's directly tied to
Experimental Web Platform features
Enables experimental Web Platform features that are in development. – Mac, Windows, Linux, Chrome OS, Android, Fuchsia
Thanks, I've now reverted all "quick fixes" in the current Snap! dev version.