SavMartin
Rectify feature is disabled for some reason
Rectify button is always greyed out. (Selecting entire island is same)
Blender 4.1 TexTools 1.6.1
This is a known limitation. While you have UV Sync Selection ON, most TexTools utilities used to be disabled due to limitations on the original version of the code. We've been adding support to it, but some tools, like Rectify, are still in our TODO list as they're more complicated to redesign.
It's worth noting that sync selection (with an improved sync system) is likely to become the default UV behavior starting with Blender 5.0 in November. https://projects.blender.org/blender/blender/issues/78393 https://projects.blender.org/blender/blender/issues/136817
