Focus issue in PuTTYNG session after switching tabs

Normally, when a SSH session has focus and you click on something to take focus away (e.g. click on the taskbar or another application), if you then click back on the titlebar of the mRemoteNG window, focus is returned to the SSH session correctly.

However, if you switch tabs just prior to taking focus away from mRemoteNG, then focus doesn't return to the SSH session correctly when you activate mRemoteNG again.

Try this:
Have 2 SSH tabs open (using PuTTYNG) with focus currently in the first tab.
Click on the tab header for the 2nd tab and notice (by looking at the text cursor) that the 2nd SSH tab now appears to have focus.
Click an empty spot on the Windows taskbar to take application focus away from mRemoteNG.
Click on the titlebar of mRemoteNG.
Notice that the focus does not return to the SSH session.

I'm running mRemoteNG Beta 3 on Windows 10.