I have floating toolbars setup to launch programs (web browser, editor, etc.). If a file is highlighted in a DOpus window, clicking on a toolbar icon will pass the highlighted file name to the program being launched. This is unwanted and odd behavior.
That is not a bug; it is entirely intentional.
To prevent it in an existing button, edit the button and remove {filepath} from the command.
To prevent it when creating new buttons by dragging programs to a toolbar, hold Ctrl down when you drag.
More detail under Editing the toolbar: Add a button that runs an external program.