Blurry UI

[long merlin]

The texture for the OptionButton itself and the panel for the PopupMenu share the same resource, OptionButton displays properly but it is blurry in the PopupMenu.

Texture Filtering is set to Nearest project wide and on this object.

[near trellis]

I think usually this happens with pixel fonts when the font size isn't correct

If fiddling with the font size for PopupMenu in your theme doesn't work, then you might also be able to change anti-aliasing to "None" in the font import settings

[long merlin]

The font size is fine, its the texture on the panel itself.

The font itself is fine I mean, its pixel perfect. The texture on the PopupMenu itself, the panel, is blurry

[long merlin]

So it turns out the Default Resource Texture Filtering Option inside the PopupMenu itself is set to linear regardless of the project settings, this seems like a Godot bug. I don't know how to manually set it.

[vagrant pewter]

I don't know how to manually set it.

This should propagate it from the OptionButton's viewport:

option_button.get_popup().canvas_item_default_texture_filter = option_button.get_viewport().canvas_item_default_texture_filter