Keka opens the progress window on the wrong desktop

**Describe the bug**
When using Keka in a active desktop different from the one Keka was started, Keka inadvertently opens the progress window on the latter, forcing Mac OS to switch to that desktop.

**To Reproduce**
1. Start Keka manually in the any desktop (usually the first one at startup).
2. Move to a Finder window on another desktop (usually ^Right or ^Left or swaping with 4 fingers).
3. Double-click on any archive to unpack it with Keka or use the Keka window to pack one.
4. The progress window opens not on the active desktop, but on the previous one, causing Mac OS to move focus and change to the previous desktop without the users command.
5. The unpacking ends and leaves the user on the wrong desktop, the original Finder window and files not to be seen.

**Expected behavior**
The progress window should appear on the same desktop the command was issue, regardless of the desktop where Keka was started. This is the expected behaviour for every multi-window application in Mac OS. If several packing/unpacking operations were started in multiple desktops, their progression windows should appear each on respective desktop, not forcing all together in the same one. The completion notification does not have this issue, since it appears "hovering" on every desktop, allowing the user to know a operation has been completed on other desktops.

**Additional context**
This problem is specially disturbing for heavy users that work with several desktops and large archives. Keka keeps throwing you back to the first desktop every time you need to pack or unpack an archive.