If your TM (or other SAP HTML UI) hangs in the Internet Explorer (including the NWBC) this might have a small and a bit surprising reason:
The Zoom. It shall be 100%, otherwise you can have very slow or eben hanging UIs.
You can define the zoom factor in the IE here:
( The Sreenshot is from IE 9, IE 8 has is somewhere else…)
So always stay with the 100%, less is more in this case :->
If you are interested in more details about TM UIs, you might listen to TMP006: UI basics…