This fancy extension addresses a quirk where GameMaker games cease to update while the window is being dragged around or resized.
The issue is Windows-specific behaviour - unless you run game logic and rendering on separate threads, system's dragging/resizing logic overtakes anything else and no other code executes until that's done.
The approach this extension takes is best called "a delightful hack" - the DLL starts up an simple helper program, into the window of which the game's window is then inserted as a child window.
This has the game window continue to run while the window is being manipulated, as well as allowing to enable/disable the window frame, allowing to also use it for borderless fullscreen.
The extension also includes it's own versions of Window Commands functions.
Documentation coming soon. Till then, see the included object for examples and disable standard border in Global Game Settings - Windows - Graphics.