This is easy to test if you have no stickers. It should no longer have
a weird empty space above the placeholder message.
(cherry picked from commit a909ed498f)
First, the fill mode for the sticker images shouldn't stretch them.
Also make sure there is enough padding in the category so the image
doesn't appear larger than the button. Finally, set the source size for
the images so Qt can smooth them out better.
(cherry picked from commit 16f4e17e8f)