Import for example sample of "Mortgage Process"
Open MortgageApprovalProcess.bpmn
Click on connection outgoing from gateway
Click in "Diagram properties"
Click on "Implementation/Execution"
In "Condition Expression" choose "Condition"
Set something in "Process Variable" and "Condition" (choose another connection if empty)
Save it
Try to edit it again and choose Reset
Try to save it again (You will receive message: "You have no unsaved changes"
If you remove it from expression field and save ,will be successful
Description
In Business Process we can't reset "Condition" in "Condition Expression" if you didn't have cleared "Expression"