Hi Jonas,
This error is common in Oracle Java application. Sometimes when you have an unattended pop up window or if the oracle screen is in noneditable format, you get the Target of invocation error while performing any action to the screen.
Please make sure you refresh the oracle window and check for popups before proceeding to edit. Hope it resolves your query.
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sahana mohan
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Sahana Mohan
Lead Software Engineer
SS&C Blue Prism