1) Which version of IE do you use?
2) If IE 9: Are you running IE in Compatibility mode?
3) What is the language of your operating system (OS)?
Things I've noticed:
- Double click works fine in IE 9 (without Compatibility mode), Firefox, Chrome and Safari.
- It doesn't work on IE 7 and IE 8.
- In IE 9 it doesn't work if you have enabled the Compatibility mode.
Also I've noticed that some functions doesn't work proper on a non-English OS.
However (as a workaround) 'SHIFT + left mouse click' works with all browsers (even IE 6).
System: MapGuide Open Source 2.4 as well as AIMS 2013 with Apache on Windows Server 2012 (German OS)