The custom software UI isn't compatible with or doesn't implement basic operating system windowing features.
I'm not sure why using custom window framing is worth the hassle just for a fancier title bar, but the current software misbehaves in many situations and ignores basic placement commands.
Currently the software maximizes over the task-bar on Windows and ignores window snapping/tiling. It also can only be grabbed/moved by the title bar, which can be accidentally moved off-screen or placed underneath the task-bar. Once this happens the window is unmovable because it doesn't implement the right-click move command, and ignores tiling/placement. Because the window remembers its previous position, closing and reopening the software doesn't fix the issue. Your main option is to reset the cached window positions in the operating system.
Please return to the standard windowing/UI system (or at least give us an option). It simply works with the features available in the operating system without kludging things.