The large triangle below the Finder is the indicator.

This long triangle is the DefaultIndicator. Change this.

It will not be displayed unless the "Running Application Indicators" of "General" in the RocketDock settings is checked.

This is the indicator of this round dot.

If you download Catalina Skin, it comes with it.

Open "Defaults" in the folder of RocketDock (Windows (C :)-> Program Files (x86)-> RocketDock).

Open "DefaultIndicator" in it.

Indicator.png is included.

Create a folder "DF" and put it in it.

Insert the Indicator.png you want to change.

RocketDock must be closed before it can be changed.

When you restart RocketDock, the changes should be correct.