When a VST3 plugin window in Cubase gets resized, for example by the size of two (double width, double height, there is a scale option in my plugin), and the plugin rectangle goes beyond the bottom or right screen border, it seems the native window will be limited to match the screen border.
So far so good.
But now we have a big problem. The plugin still uses the non-limited width/height coordinates.
So a part of the plugin goes beyond the window, the plugin is only partially visible, even if I move it away from the border.
This must be somehow fixed.
Maybe use a 100ms timer after setNativeHostWindowSizeVST has been called, which checks the actual size of the native window, and synchronizes the internal width/height coordinates of the plugin window.
In ProTools AAX I have noticed a similar behavior.