Thank you for your suggestions.
Regarding your first issue, the dialog window may behave in such unusual ways very occaisionaly and may happen with any window. All you need to do in such situations is to click the application icon in the task bar and it'll appear.You need not close the app.
Regarding the preferences option to be incorporated in terms of- encryption options, destination and delete original file can be done for sure and i would look towards that in the next version release of Conceal. However having a file-menu based options would make the whole Interface look very conventional and that's what Conceal scores at.

The English and German versions are only a part of setup-language preference and have no effect on the software itself. I would also try and include Italian as a setup language preference for the next version release.

Thank you again for providing your suggestions & improvements. They are indeed valuable.
- Author