Button overflows on click

Don't know if this is a bug exactly or if it's a problem with Ristretto itself. When you click on the arrow buttons in toolbar to advance to the next image or return, the button "overflows" the area. Seems that it only can be triggered when images are of a certain size, bigger than 1mb on my case.

video01

Steps:

1. Set Adwaita gtk theme.
2. Open an image in Ristretto from a folder that has at least 2 images bigger than 1mb.
3. Click the button to go to the next image or to return.

Saw this occur only with Adwaita and Adwaita-dark theme. Tested with Greybird, Numix, Materia and Plata themes, and it does not happen with them.

Using Xubuntu 20.10, Xfce 4.16 and Ristretto 0.10.0.