(from bug 49922 comment 1)
VE is slow at selecting templates and transclusions in big pages.
For example: [[World War II]]:
- attempt to select infobox by clicking on it: takes ~3 seconds in Firefox 21 and Chrome 27, with no visual indication that anything is happening during the wait
- attempt to select the reflist by clicking on it: just hangs in Firefox and Chrome, never actually seems to happen
This either needs to be sped up, or fail more gracefully.
In IE10, this is not such a problem \o/ - lag is actually less, and the reflist can be selected (takes about 22 seconds).