I found a small bug. If you have no files open, drag a folder to the sidebar to open a project, ctrl+p and preview the files but don't actually select a file (escape out of the quickpanel dialog), the last file you previewed is still shown in the editing area (the same as if you would have opened it) but the file is not added to the open buffers list. I guess if you cancel in the quickpanel when no files are opened that the editing area should be cleared.
Up/down arrows still do not scroll the quickpanel view, but the resizing is now remembered.
Is there any way to hide the window decorators of the quickpanel like in the "old" SublimeText...I thought it looked much nicer.
It might be nice to have "expand all" and "collapse all" options for the projects.