[ol][li] Edit the toolbar and remove the "hideempty" argument from the item which lists the drives.
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[li] The purpose of checkbox mode is that the selection (checkboxes) used for things like the Copy and Delete commands can be separate from the selection (traditional selection) used by mouse actions like right-click and drag & drop. Checkbox mode exists to let you build up a set of selections for a big task at the end, while still being able to perform several smaller tasks along the way.
Instead of using checkbox mode, you might find a better fit for what you want in normal Details mode (where you can click files with the middle mouse button to toggle their selection without affecting others', like ctrl+left-click but without having to touch the keyboard), or one of the Power mode configurations (where you can have toggle-select on the left mouse button, or various other options).[/li][/ol]
Optical drives in toolbar: Problem solved, but next time please be more explanatory - edit the toolbar and remove the "hideempty" argument actually means, as I discovered: go to "C:\Users\user\AppData\Roaming\GPSoftware\Directory Opus\Buttons" and edit "Drives.dop" with a text editor to remove "hideempty" argument
Checkbox: I disagree - I believe that once you have selected the files (using thumbnail mode) you should drag, delete and do whatever you want with them with no further actions, but it's your call
thank you!
Sorry, it's hard to guess how much help each different person needs. Editing the XML files directly is doing things the hard (and risky) way. See Editing the Toolbar in the manual (also available by pushing F1 in the program) for instructions on toolbar editing.
I think the other modes I mentioned should give you want you want; checkbox mode isn't the one you want here, it's for something different.