Weird spacing for numeric inputs

[FichteFoll]

Since some update of wx, iirc, numeric inputs that have the up and down buttons attached have really odd spacing. I suspect their layout was changed in some wx update.

This is a recent master build on Arch (both this fork and original), but has been present for a longer time. Something between 0.5 and 1 year, probably?

Screenshots below:

Also results in a lot of

(aegisub:12152): Gtk-CRITICAL **: 05:02:20.204: gtk_box_gadget_distribute: assertion 'size >= 0' failed in GtkSpinButton

messages on the console.

[FichteFoll]

In a similar fashion, some combo inputs are too small with their default width:

I'm using the Arc-Dark-solid Gtk theme, btw.

Here's how it looks with Adwaita: