Extensions with space in name get created in nested folders

[yadvr]

problem

When creating extensions with space, the form strips the space:

But after it's created, the space is replaced with _ (underscore), and the actual extension is nested in a folder with out space in its name:

versions

ACS 4.21 RC4

The steps to reproduce the bug

1. Create extension with space in name
2. See path after creating the extension
3. Now see the nested directory structure
   ...

What to do about it?

Nested directory shouldn'be created; I like the stripping of space in name instead. Also haven't tried other things like special characters etc. Those may be checked as well.