Changes to default project theme don't update right away

[AaronRecord]

Godot version

ea4b8de

System information

Windows 11

Issue description

Setting the default project theme for the first time:

2022-08-03.14-28-10_Trim.mp4

After restarting editor:

2022-08-03.14-30-51_Trim.mp4

In theory I don't see why this should require an editor restart in the first place. Also as a side note I think the project default font could be removed as well as you should already be able to do this by assigning a default project theme with a default font.

See also #62844

Steps to reproduce

See above

Minimal reproduction project

MRP.zip

[AaronRecord]

Some other possibly relevant issues I found:
#39785
#48477
#56520
#60930

[KoBeWi]

Interesting...

godot.windows.editor.dev.x86_64_hxyDxnVQQT.mp4

(it's the same in 3.5 btw)

[YuriSizov]

Yeah, of course. There is simply no mechanism for propagating global theme changes to controls. But there will be.