dde-file-manager shrinks on enabling picom/compton

[bonecountysheriff]

(Originally on picom's issues page, yshui/picom#272. The developer suggested to move it here. I've tested this on compton too.)

Platform

Arch Linux x86_64

Environment

i3-gaps

picom version

v7.5

Configuration:

default

Steps of reproduction

1. Install i3-gaps and deepin-file-manager from the official arch repositories.
2. Start i3-gaps using xinit or lightdm
3. Run dde-file-manager.
4. Now, start picom.

Expected behavior

The gap size should be as expected.

Current Behavior

current gap-size = expected gap-size + half-an-inch
If picom is killed by hand, the gap size goes back to normal.

Other details

As far as I know, other deepin applications look just fine with picom.
(I clipped out a small portion at the bottom of the images, it contains the i3-bar, nothing else. This is why the bottom gap looks uneven.)

[bonecountysheriff]

Just the window size. Transparency works just fine.

Expected Behavior

(without picom)

Current Behavior

(with picom)

Application on the left: deepin terminal
Application on the right: deepin file manager

Like I said, only the file manager has the issue. Other deepin applications work as expected.