Hello - I guess that there is a problem with unshared SQL worksheet in Developer 19.2.0.206 (64bit edition).
If I execute long running task in "main" connection window and I want to execute something in the unshared SQL window - then the other window code is not executed until the "main" window task is finished.
See how "SELECT 1 FROM DUAL" waits until SLEEP(50) finishes:
Anyone else can confirm this?
Pavel