I just reported this to the Scigraphica bug tracker,
but I think the issue may be with gtk extra.
I am running on a Pentium 233/MMX.
The spreadsheet in Scigraphica for entering numbers
had a huge latency (about 1 second/keystroke) until
I switched from the "Smoke" gtk theme to the much
simpler "Helix-Default". Then the latency was
gone.
If this is noy yet documented, perhaps it could be
added to a FAQ.
Is there a method to force a per application theme?
This question should be be addressed to the Gtk community.