When I import a DXF file, I select all (CTRL+A), flip it (horizontally and vertically) using the toolbar icons, then click the move to top right toolbar icon. Then I set the layer and click play.
Once the cut is done, everything is still selected, however, if I click delete, nothing happens. If I press CTRL+A again, then delete nothing happens. I have to click a blank area in the main window, then press CTRL+A and then delete to delete everything. Why…? If everything is selected why do I have to unselect everything then delete it!?
When you click on the start button with the mouse, focus shifts from the workspace to the Laser window. In order to delete the pre-selected shapes, you need to put focus back to the workspace. You needn’t actually unselect everything first but I’ve not found a simple way to put focus back to the workspace without just clicking there. I typically will just click onto the already selected shape to return focus to the workspace.
After some playing I might have a solution (maybe it can help you too), instead of clicking the play button, simply use ALT+S and that is the same as clicking the play button. The difference being that the delete button now deletes the previous selected items, thus it appears to not change window focus.