Just had this occur on my Windows XP SP2 system.
I clicked off SlickEdit, jumped around through several other apps for about 20 minutes and when I clicked back, SlickEdit refreshed but was non-responsive. The status text at the bottom said "Retagging paused"
I pulled up the task manager but vs.exe showed 0 cpu usage. After about 30 seconds slickedit came back.
Here's some info from the about box about a minute after it came back but Slickedit is still behaving very sluggishly with slow refreshes (IE while moving the mouse over the menu bar, the pop ups would appear slowly and the "Windows" option actually stayed highlighted after a hiccup as if it has missed a message)
Emulation: Brief
OS: Windows XP
OS Version: 5.01.2600 Service Pack 2
Memory: 63% Load, 1337MB/2095MB Physical, 784MB/2097MB Virtual
Shell Info: C:\WINDOWS\system32\cmd.exe /q
Screen Size: 1680 x 1050
Project Type: cpp
Language: .cpp (C/C++)
Number of tagging threads was set to 2 but I have a Pentium 4 single core (with HT which looks like 2 cores but isn't really).