File browser filter not working correctly

Question

I'm writing a python script which can open multiple files and I want to filter certain file extensions.

This code is working perfectly fine:

filter_glob = bpy.props.StringProperty(
    default='*.pmx;*.pmd;*.xps;*.mesh;*.ascii;*.smd;*.qc;*.vta;*.dmx;*.fbx',
    options={'HIDDEN'}
)

But as soon as I add ".dae" as another file extension like that:

filter_glob = bpy.props.StringProperty(
    default='*.pmx;*.pmd;*.xps;*.mesh;*.ascii;*.smd;*.qc;*.vta;*.dmx;*.fbx;*.dae',
    options={'HIDDEN'}
)

the filtering stops working entirely and every file is shown. I have no idea why this happens and it looks like a totally random issue to me.

Does anybody know what happens here or how I can fix it? Is this a bug in Blender maybe? Thanks!

Answer 1

I reported it and it turns out that it is indeed a bug. It will be fixed in Blender 2.8.

Link: https://developer.blender.org/T55503