How can I automatically show the FULL PATH of the currently loaded document (not just only the file name) in the title bar of Apache Open Office 4, e.g. OO-Writer?
I think this is a feature that has not been implemented yet into OO. You could achieve a similar result by displaying the URL in one of the toolbars, instead of the titlebar. Go to View > Toolbars > Customize. Add the "Load URL" option to the toolbar of your choice.
Or, if you feel comfortable with macros, you could create one and then make it run on the "open document' event. Create and save the macro, go again to the Customize dialog and under Events, select Open document, then click Assign macro. The macro itself should be something like this: