Thanks for the answers. I was using the project manager (? - the leftmost tab; it has a blue box on it), and dragging doesn't work there - it drags the file name into tab has the focus. Doing this from the explorer does work.
The files in question are registered (in the Windows sense) to the application that uses them, which is a kind of interpreter, but because they're code it delegates editing to an external application - PSPad. So double-clicking starts a new instance of the application, which delegates to... a new tab in PSPad. I was looking to avoid that middle step. In addition, sometimes I need to edit a file the application would prefer to open and run. An option to make opening a file in the project manager default to PSPad would be helpful to me. Is there a way to request that option? I made the project to collect the files I expect to edit in PSPad for easy location. (This particular application has a number of different kinds of source files, and they use different syntax - I've made three syntax highlighting files for it so far.) -- <http://forum.pspad.com/read.php?2,65060,65094> PSPad freeware editor http://www.pspad.com
