SSMS2012 Help going to Chrome rather than MSIE

Question

Running Win7 Ent 64bit

From within SSMS 2012 SP2, when I hit F1 (or Help, View Help), I am taken to Google Chrome rather than MSIE11. By every indication I can find, MSIE11 is my default browser, not Google Chrome.

I've gone into MSIE11 and made it my default (Tools, Internet Options, Programs, Make Default). Then into Chrome, check Settings, and it tells me Google Chrome is not currently your default browser. For good measure, I went into Firefox, Tools, Options, to see Firefox is not your default browser.

In Control Panel, Set your default programs, Internet Explorer, I see This program has all its defaults. For good measure, I select Choose defaults for this program, click Select All, and click Save.

I've gone fishing around the registry to try to see where Chrome has left it's toehold, and won't give it up to MSIE11, but I'm not finding it.

Update Aug 15, 2015

I discovered a nuance to this issue. This problem occurs only when I'm running SSMS under different credentials using Runas. If I run SSMS under the AD credentials I'm logged in as, F1 correctly takes me to MSIE.