OS: Linux 64bit (Ubuntu 18.04)
After using "File -> Copy to... -> Copy" command (Alt + C) it is not possible to copy another file with Alt + C unless:
1. Alt + tab to active another application and then Alt + tab to go back. Now Alt + C works
2. Click image with mouse. However, after this arrow keys are not working anymore for browsing pictures
Effect: Not possible to use Alt + C command but once, if clicking with mouse arrow key shortcuts are disabled
To reproduce Alt + C not working anymore:
1. Open XnView browser
2. Open any picture in a folder which contains more than one pictures
3. Press Alt + C, select folder, click Copy
4. Press Alt + C
Actual behaviour (bug): Nothing happens

Expected behaviour: Copy to... dialog opens
To reproduce arrow keys not working anymore:
1. Open XnView browser
2. Open any picture in a folder which contains more than one pictures
3. Press Alt + C, select folder, click Copy
4. Click picture with mouse
5. Press right arrow key to go next picture
Actual behaviour (bug): Nothing happens

Expected behaviour: Next picure is shown