Selecting text slow on Firefox

[laggingreflex]

Selecting text takes a significant time to catch up to the moving cursor.

Screehshot (left - firefox v58, right - chrome): https://gfycat.com/LeftPresentDormouse

[makepaddev]

Probably has to do with the fact i actually copy the text into a hidden textarea to make 'copy' work since its thread-async. I'll fix that in the next rewrite.