bug or feature? unable to resize browser window

[lamoid]

When I open the file browser of xnview 0.96.5 in windows 10, it is not possible to move or resize the window. In fact all the window manipulation tools are missing: cannot close it by clicking on an 'x' in the upper right corner. It's not there. Neither are the minimize or maximize icons. I used to be able to adjust the size of the browser window or close the program by clicking on the 'x' icon. Why is that no longer possible?

[xnview]

you have not used Ctrl+F11??