Hello,
I have a specific bug happening here for not so very long.
Number properties only seem to accept commas as decimal signs (like 0,5). Oddly enough, when you select a property, it displays the current value in a point decimal sign, which invalidates the property on change.
Problem visualized:
Happens to any property containing a number value.
I don’t have this issue on Windows 8.1 . My numbers do not accept commas and work perfectly fine.
It’s to do with localizations. Set your localization to English (US) or English (UK)
Thanks for the suggestion, but I don’t feel like changing my entire Windows display language including data, time and number notation for this small issue. 
This should stay the same. In many struct types like Vector3 and UDim2 commas are used to separate numbers. If commas are changed to act like decimals this can get very confusing.
Alright, here is the deal since I’m obviously not clear enough.
[size=5]Problem:[/size]
On non-English windows computers, the single number property boxes only seem to accept comma decimal points.
[size=5]Possible solution:[/size]
Force the use of periods, even on non-English computers. I’m not asking for a change to commas.