This is intriguing me quite a lot. Its making my recent project look a bit weird because the padding lines change width unexplainably, and sometimes are kind of gone.
I made a quick project to recreate the issue, this is what is happening, at runtime, sorry its barely perceptible:
I made a video that shows the problem clearly.
As you can see the padding is bugging unexplainably, the right and left padding even though they have the same padding (4.0), the left padding is thicker than the right padding.
Any idea what could be causing this?
This is happening with Grid, Vertical and Horizontal box.
Inside of your icon widget your grid panel is throwing off the size interpretation. GridPanel_682 for some reason has two row fills with some very small number in the second entry causing the image to have a different proportion in relation to the outer size module.
Instead of nesting so many borders look into the 9 slice method for your portraits.