How to open the same file in the current Editor if it was already opened in a separate window

Situation

1. Open a file in the Editor by double-clicking on it in the Project tree
2. Drag it away from the Editor area to open it in a new separate window
3. Try to open it again in the Editor by double-clicking in the Project tree
4. Observe how the window dragged on step 2 gets focused again

Question

How to open the same file in both windows simultaneously?

Answer

Go to Settings | Advanced Settings, and disable the option called "When navigating to a file, prefer selecting existing tab in inactive split pane":