Leave trendlines on chart after inactivating indicator

As the title says - is there a way to leave the trendlines, drawn by an indicator, on the chart when the indicator is removed? I've tried things such as overriding the StopCalc()/Destroy() methods in case the code to delete the objects were there, but it didn't work.

Since we can access trendlines by specifying EDrawingSource, may it's possible to overwrite this property to 'manual' or similar?

Thank you in advance.

Hello QGroup,

Please enable the corresponding option in File -> Preferences -> Charting tab: