Configuring an Issue Tracker slows down the creation of the commit widget significantly
When an issue tracker is configured, the creation of the commit widget takes significantly longer than usual because TortoiseHg creates the COM object that talks to the Issue Tracker plugin in the Commit Widget constructor.
This can take a significant amount of time, even on a pretty powerful machine (e.g. loading the JiraSVN plugin takes more than 0.4 seconds on a modern PC with a quad-core CPU, 8 GByte of RAM and an SSD hard drive). I've seen older machines take several seconds to create the commit widget because of this. Creating the COM object "freezes" the TortoiseHg workbench GUI.
Since this must be done for every repository, the effect is a significant slowdown of the TortoiseHg workbench.