ScrollBar StyleBoxTexture Grabber only half usable?

[rakkarage]

Tested versions

Reproducible in:

• v4.4.dev.custom_build [4c4e673]
• v4.3.stable.official [77dcf97]
• v4.2.stable.official [46dc277]
• v4.1

System information

Godot v4.3.stable - Ubuntu 24.04.1 LTS 24.04 - Wayland - Vulkan (Forward+) - dedicated AMD Radeon RX 6600 (RADV NAVI23) - 12th Gen Intel(R) Core(TM) i5-12400F (12 Threads)

Issue description

When using StyleBoxTexture for scroll bar only half the grabber is usable. The other half just click thru the grabber onto bar.

Thanks.

Steps to reproduce

• make a scroll bar use StyleBoxTexture from theme.
• grab.

Minimal reproduction project (MRP)

https://github.com/rakkarage/test-scrollbar-grabber

[rakkarage]

The problem becomes a bit clearer when not use 'Expand Margins' to reach edges.
Maybe this is the real problem? That grabber not line up with edges?
Here the grabber can be grabbed in the gap between bar edge and grabber.

I thought this was how it worked, if use StyleBoxTexture need to use margin (top and bottom) to expand to (VScrollBar) edges... and margin (right and left) to expand to (HScrollBar) edges. But maybe not.

[WhalesState]

You don't have to use expand margins, you can set the content margins of the HScrollBar scroll StyleBox to zero for left and right, and the VScrollBar scroll StyleBox to zero for top and bottom, this will make it ignore the texture margins.

Additionaly, the content margins are not respected for mouse input, which is what i'm going to fix for this issue.

Here's the project after applying the changes. test-scrollbar-grabber-main.zip