Fix commented check in LayoutAnchorable Hide method

[gpetrou]

No description provided.

[Dirkster99]

Hi, thanks a lot for the pull request - I'd realy like to merge it into the code and release a new version but I need to better understand what the problem is that we are fixing. I could off course be going off and be doing guess work but I prefer communication :-)

Would you be able to give me a short description for this fix? It would, for example, be enough if you give me a short list of test steps and an expectation to verify how the software behaves with and without your fix.

Thanks Dirk

[gpetrou]

Sorry, I should have added some description.
I did not find a bug, but while looking at the code for something else, I noticed that inside the brackets we have Parent as ILayoutGroup and then access IndexOfChild. Unless I am mistaken and Parent as ILayoutGroup is guaranteed to not return null?

[Dirkster99]

You are correct with your analysis - but what about my analysis over in #33 ?