I have spent about one hour of spare time making this silly converter, which could still help you in some situations where you need fast conversion between an hexadecimal and a decimal value.
The tool can be reached by rightclicking the pattern editor or through “Pattern Editor:Tools:Hex-Dec converter” shortcut key.
I have one unresolved issue with the code, though: I had to put two buttons to actually perfomr the conversion because putting conversion code into the change notifiers of the two textfield would create a feedback loop (user change text in Dec textfield => the Dec notifier triggers and changes the text of Hex textfield => Hex notifier triggers and changes the text of the Dec textfield). -> split to [Fixed 2.6] Error While Removing Notifier From Textfield