I am running stock Xubuntu 16.04.
When I take a window and try to snap it to the side of the screen in 50% mode, it switches my workspaces instead.
How can I disable this behavior such that dragging a window to the edge of the screen does not switch my workspaces?
In Xubuntu, the default behaviour of window manager is to move the dragged window between workspaces. This behaviour becomes effective when having two or more workspaces (Xubuntu 16.04 uses only one workspace by default, thus ineffective at first).
To disable the behaviour, follow the steps.
Go to Settings > Window Manager.
In Advanced tab, under Wrap workspaces when reaching the screen edge, look for option "With a dragged window". Uncheck the option (leave the checkbox empty).
Close the window to finish.
The following screenshot shows before and after making changes to the option.
Now whenever a dragged window reaches to the screen edge, it will not switch to other workspaces. It will instead snap the dragged window to the half of screen (also the default behaviour).