Created attachment 180846 [details] steps to reproduce SUMMARY Transform Mask works fine when the group it applies to is the same size or smaller than the canvas. However, it produces incorrect result when the group is larger than the canvas. STEPS TO REPRODUCE 1. Create an empty file. 2. Create a layer and fill its content so it's the exact same size as the canvas. 3. Put the layer in a group 4. Add a Transform Mask to the group 5. Transform the Transform Mask, for example, scale it down. 6. Select the group, and use Transform Tool to transform the group, for example, scale it up so the content is outside of the canvas There are some nuances, so please take a look at the attached screen recording. OBSERVED RESULT Very corrupted result. EXPECTED RESULT Correct result. ADDITIONAL INFORMATION This bug only happens when the Transform Mask is applied to a group. It doesn't happen to a simple layer. Note that in step 6 we need to transform the group (not the layer, nor the mask) to trigger this bug. There was a similar bug here: https://bugs.kde.org/show_bug.cgi?id=427187 But this one only happens with group, so I don't think it's the same bug. SOFTWARE/OS VERSIONS Qt Version (compiled): 5.15.7 Version (loaded): 5.15.7 OS Information Build ABI: x86_64-little_endian-llp64 Build CPU: x86_64 CPU: x86_64 Kernel Type: winnt Kernel Version: 10.0.19045 Pretty Productname: Windows 10 Version 2009 Product Type: windows Product Version: 10