POV-Ray : Documentation : Keep Single Instance
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3.5.8 Options Menu Use Render Animation Keep Single Instance

This option prevents more than one instance of POV-Ray for Windows from running at a time. If you attempt to launch a new one, the currently running one is activated instead. This is handy if you are using File Manager or Explorer to launch POV files by double-clicking. (Explorer users can get even more control by using the right mouse button menu.)

3.5.8 Options Menu Use Render Animation

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