I had to do some work in a Silverlight (I know, I know) application recently.  One of the features I was working on is to show a web page in out-of-browser running Silverlight application.  The page is a modern page that I wrote using Angular JS.  What I found is that as soon as the page is shown, an error comes up – “object does not support property or method addEventListener.”  Obviously I am using an older version of IE when WebBrowser control is loaded.  How do I address this problem?  It took some serious digging, and I finally found a workaround on this page.  By default, IE is running in IE 8 mode.  I had to change the mode to IE 9 in two places in the registry:

HKEY_LOCAL_MACHINESOFTWAREWow6432NodeMicrosoftInternet ExplorerMainFeatureControlFEATURE_BROWSER_EMULATION

HKEY_LOCAL_MACHINESOFTWAREMicrosoftInternet ExplorerMainFeatureControlFEATURE_BROWSER_EMULATION

I changed the setting for sllauncher.exe key name to be 9999 (or 270f hex).

I reloaded off-line app, and it worked!

Enjoy.