If we knew exactly what code Mike changed then perhaps you could change that portion of code back -- but then you'd have to reapply those changes during future upgrades.
So honestly if you were already muddling through by only being able to do it using Chrome then perhaps a more robust solution is needed anyway.
If you're absolutely adamant that you need to paste an image from Excel to XenForo, then you might want to look at using a screen capture tool such as the Snipping Tool that's built into Windows (from Vista onwards).
Click and drag around an area of your screen, it will open it up in a Window. You can then copy that to the clipboard (or save it) then paste that into the XenForo editor which will automatically attach and insert it.
Seems to be the equivalent functionality. I use it all of the time. Even on my Mac I use the Grab tool which is basically the same thing.
If you had a need to create tables directly in your XenForo add-on then there is a couple of solutions by @
Waindigo that might be useful. Specifically the tables one and the one that allows the tab key to be used.
These may allow you to format your tables directly in XenForo without the need of Excel. But if you still need to use Excel then I think my screen grab idea is probably optimal.
