Browser: Latest (UXP-based) Serpent 52.9.0 (2022-02-25) (32-bit)
Browser profile: Fresh/clean one (with default settings), only this extension installed
Extension version: Latest release, i.e. v1.12.15

STR

1. Load in a tab, e.g. 8446565 (#48)
2. Click the Load diff area; diff will display correctly 👍 .
3. Now normally reload that same tab; depending on the time of day (i.e. completely random 😸 ), you'll either get a misplaced and disabled Load diff button like below:

or a correctly aligned Load diff button, but disabled nonetheless 😠 :

Since we know that the code that addressed #46 is already inside v1.12.15, and with me not being a coder in the slightest, I'd hazard a guess that some type of race-condition is taking place that prevents that code from actually functioning... Perhaps it has to be the last to run (or is every polyfill inside the extension injected asynchronously?) ?

As already noted in #46, CTRL+F5 will, again, restore things...

PS: The SeaHOH fork is also plagued by the same issue currently (at least for me, that is...).