I am a very limited user of the alternative image editing app, doing very basic functions to tweak my images to my liking but nothing extensive at all. One thing that I usually (always) do is adjust for image distortion and perspective convergence. Being a huge fan of view camera "tilt-shift" capacity, I usually do some perspective correctionof any image that has a building (or buildings) contained in it.
When using the "perspective" option under filters>distort>perspective, the grid would be SO helpful if it were not altered with the image, so there were reference points (vertical and horizontal) to what the correct planes were. I could see the perspective change, but the grid would always tell me what was perfectly horizontal and vertical, I could align my building edges up with the grid as opposed to what I thought was perfect vertical plane (of visually "thought" was). I hope this comes across... I am a real stickler on this one specific area.
I included the image (screenshot) to show you how, along with the image itself being changed, the grid too converges, eliminating any/all reference points in order for me to create a convergence free image.
Hopes this helps...