null-pointer exception in RendererDX11 on DPI change

[connorjak]

In my app which is derived from the Blueprints example (https://github.com/connorjak/Connectatron/tree/3547d2daa75070b9082aeedbc1d32b2838dc40e7), there is a null-pointer exception in RendererDX11::RenderDrawData() on mouse-release after dragging the window across a boundary between my 200%-scaling main display and 100%-scaling second display:

imgui-node-editor version: https://github.com/thedmd/imgui-node-editor/tree/6c834d837fdd50f58e4ba6b436ab8c3eb0500743