Buggy behavior when adding a class property that has a space in it's name

I tried to add a property that had a space in it ('Target Date'), like I've seen on http://www.theserverside.com/news/1363830/XWiki-A-Platform-for-Collaborative-Apps

After pressing 'ADD' on step1.png, the UI is in waiting like seen on step2.png. I couldn't delete the added property because it said it didn't existed. The only solution I had was to refresh it, that revealed step3.png

When trying to add properties that have special characters in them (like /) I had errors.png.

I don't know why we are not allowed to have spaced in names (like seen on the errors messages), but this error message was not revealed to me when trying to add such a name.

The current buggy solution is much nicer. The editor removes the spaces and creates a property 'TargetDate', the only thing is that the refresh should be fixed and the UI should not hang out like in step2.png state.