I have them both installed and still get that message.
And I got some wierd behaviour when changing a name of an object and focus on an other object.
(Cant remember the exact error, but I can reproduce the error)
It's all good when I change a name and focus an other field in that object though.
I get the 4.5.2 message as well. I tried reinstalling the latest .NET Framework just in case, and the installation reported that 4.5.2 was already installed. However B4A Designer still announces "Install 4.5.2 for better operation ..." I have to say though that B4A and Designer both are working great, so I suspect the Designer message is incorrect.