7.53 update seems to have broken the script editor's horizontal scrollbar. It's maxed out from the get go, doesn't adjust at all and is extremely sensitive.

Almost certainly related to this fix:

https://forums.mirc.com/ubbthreads.php/topics/264369

I hadn't noticed it because I'm used to navigating with End/Home/Ctrl+left/right_arrows.

Thanks for your bug report. This is indeed related to the fix mentioned by maroon.

The current fix sets both EM_SETTARGETDEVICE and a unicode character to fix the text-wrapping issue. If I disable the use of EM_SETTARGETDEVICE, the unicode insertion seems to resolve the text-wrap issue sufficiently well and the horizontal scrollbar is back to normal, so I will use this in the next beta to see how it works out.