Black vertical line occurs when using 2 screens

[MnguniCoder]

SumatraPDF version

• Version 3.7.18095 64-bit Pre-release

Describe the bug
When using 2 screens a black vertical line is visible either to right of the screen or left of the screen depending on which screen is sumatra pdf is open in. Problem occurs only after full screen mode exit.

To Reproduce
Steps to reproduce the behaviour:
Make sure you have 2 screens set on extend.

1. Open any document using sumatra pdf. Make sure sumatra pdf is only displayed on 1 screen and it is maximised
2. Press F to go full screen on sumatra
3. Press F again to exit full screen
4. You will see a vertical line on the other side of screen where sumatra is not opened.

Expected behavior
No vertical line should pop up on either screens

[GitHubRulesOK]

Hmm I think that may be hard to emulate without specific hardware

In my case the screens are diagonally offset and when expanded to either screen using full screen and then reduced on the join there is no sign of edging both cases look like this the "LINE" is from the hardware layout

[MnguniCoder]

2026-04-05.16-07-14.mp4

The problem occurs if you press f to go full screen than press f again to exit the full screen
Hardware {Intel Core i7 - 8550U 32GB Ram}
Display resolution on both screens is 1920 x 1080
One screen is my laptop screen the other is DELL SE2422H monitor

[kjk]

Does it happen with default light theme?

[MnguniCoder]

Yes it dose. This time the edge changed colour to look transparent. If you zoom in the picture you will see it. The stable version 3.6 dose not have that problem

[kjk]

Please let me know if 18121 fixes it (you can do Ctrl + k, "check for updates` to update within

[MnguniCoder]

No it did not fix it. Problem still persist

[GitHubRulesOK]

@kjk zoom in to the lower right corner of the sumatrapdf window and see the curved edging it seems there is a small ghost line around the translucent border edging I dont see that in 10 but may be an 11 artifact