Popup's can't have transparent background anymore.

[azagaya]

Tested versions

Reproducible in 4.2.stable

System information

Windows 11 and Ubuntu 23.04 Godot 4.2 stable, Vulkan Forward +

Issue description

When using a stylebox (either texture, empty or flat) that does not cover the entire rect, the back of the popup will use the clear color instead of being transparent, which causes unpleasant results. This was working ok in 3.x.

This image is an example of an option button, whose popup panel has a style of a rounded flat box.

Steps to reproduce

1- Create option button
2- Add a StyleBoxFlat to the "panel" in the PopupMenu theme.
3- Round the corners of that StyleBox
4- Add items to the option button
5- Run the game and test the option button

Minimal reproduction project (MRP)

ThemeIssues.zip

[AThousandShips]

Have you set transparent and transparent_bg true on the Popup?

[azagaya]

@AThousandShips hey, no i haven't. How do i set transparent to true in the popup of an optionbutton?

[AThousandShips]

You get the popup with get_popup

[azagaya]

@AThousandShips so if i want to use a theme that has a style like this, i need to also add a script that does this? I only want to have themes and be able to change them.

[azagaya]

Adding a script that sets transparent_bg to the popup returned by get_popup works. However this is a bit unusable for theming, as you would have to do this on everything that has a popup.

[AThousandShips]

(please don't tag me, it's just us here, I don't need the additional notifications)

This is a limitation, transparent backgrounds are expensive and it's not possible to just detect this easily, so it's something you need to do manually

If you want to change this you need to open a proposal as this isn't a bug, assuming it works with the correct fix

[azagaya]

Ok, sorry for the tag. I'll look into writing a proposal.

[AThousandShips]

Closing as per the above 🙂

[kleonc]

@azagaya See #76071, #81669 (comment). For a potential workaround idea see #76071 (comment) (you'd need to tweak it to your needs).