macOS Objective C: When is a HWND not isKindOfClass:[NSWindow class]?

[juliansader]

I am trying out some code for Apple, using Objective-C.

AFAIK, I am supposed to check whether HWNDs are usable, using

if ([(id)hwnd isKindOfClass:[NSWindow class]])

However, this seems to always return false, even for standard REAPER windows such as the MIDI editor, returned by MIDIEditor_GetActive.

[Meo-Ada Mespotine]

I don't know, if that helps, but as far as I could see, no hwnd on the mac-version of Reaper has a class-name available using JS_Window_GetClassName.
So maybe, it isn't available that way on Mac.

[juliansader]

To answer my own question, as far as I understand it: the child HWNDs inside a top-level parent window are of class NSView, and only the parent is the NSWindow. (And the ContentView is the highest accessible NSView object in the window’s view hierarchy.)

Some functions, such as setting opacity, only apply to NSWindows, so to get the NSWindow that contains the NSView (corresponding to a WDL/swell HWND), one can use:

NSView* view = (NSView*)hwnd;
NSWindow* window = (NSWindow*)[view window];