[quote=koja]
2) made sure nls_sort from backend and client matched(registry - Oracle home) [/quote]

NLS_SORT according to Oracle Documentation

"NLS_SORT specifies the collating sequence for ORDER BY queries."

Nothing to do with any kind of client performance.

Performance is definitely the issue, we all knows that, but despite of that is PLSQL Developer one of the best tool of the market, so, we have to try keep calm everytime hellish delay happens (and some days its pretty often
In my opinion problems are related to connection handling, multiple connections are more "addition" than integral part of application (why is there some "main" connection?). The hell comes when you try to use more connection at the same time and some of them are not available (eg you discconnect the vpn...) even if you tell the developper to close the connection, it sometimes "try" (=at least 30sec timeout) .. Another problem is poor tuning of system/dba queries (to get the oracle catalog data), you can try the checkbox "use DBA Views if avaliable" but it doesnt help much.
But as I wrote, for developer there isnt something really better

Worker,

Thanks for your tip:

[quote]Turn off Preferences->Connection->Store recent history[/quote]
That worked nicely for me.

- Stew