Selected step in the test can be dragged and dropped in the same test only. Extend the functionality to be able to drag and drop the steps between the opened tests. 

Currently there is an alternative to reuse the steps between tests - you can copy a step and paste it into another test. Choose between the step context menu options, or the standard keyboard shortcuts for these operations (Ctrl+C and Ctril+V). Select mulitple steps using the Ctrl and Shift keys along with mouse clicks for selection - selecting sequent items using Schift key and selecting non-sequent items with Ctrl key. The copy/paste/cut/delete actions also work for multiple steps selection.