Hi,
is there any kind of limit (to what). I am in such a situation that it generates Outlook mails with subject:
"PL/SQL Developer error: List index out of bounds (50)"
in an endless cycle

9.1 PL/SQL Developer: Version 15.0.3.2059 (64 bit)
01.145995 - 1 user license
Service Contract:_01.01.2024
Style:_Windows 11 Dark
Windows 10 Build 19044
en-US(1033)/English (United States)
9.2 Parameters : C:\Program Files\PLSQL Developer 15\plsqldev.exe
9.3 Preferences : Session mode:_Multi
OCI Library:_<none>
Use OCI7:_False
Allow Multiple Connections:_True

Can you go to Preferences > User Interface > Options, press the "DSA Dialogs" button, and copy the text in a reply?

;Shows a list of dialogs that have the "Don't Show this message Again" option checked
;You can delete lines for the messages you want to enable
CDIFFUSER=6
NotAllRecordsWarning=1
DeleteAllRecords=6
AutomaticStatisticsDisabled=1
ClearBookmarks=6
ExceptionAt$0042B46B=1
ViewStackDump=7
ProfilerDeleteRun=6
UTF8EditWarning=1
SCEXPIREING-01042016=7
SCEXPIRED-01042016=7
NotAllRecordsCopyWarning=5
SCEXPIREING-01012020=7
SCEXPIREING-01012021=7
BrowserExpandAll=6
ExceptionAt$007340B9=2
View.xml=7
SCEXPIREING-01012023=7
ExceptionAt$005ACE8D=2
View.html=7
Edit.html=7

Can you remove the lines with "ExceptionAt"? When the error occurs again, click on the "Don't show this message again" option and click on the "OK" button to close the message box.