Make wxFrame::EnableFullScreenView() work under macOS 10.11+

We must explicitly turn on NSWindowCollectionBehaviorFullScreenAuxiliary
flag to prevent the window from becoming shown in full screen.

Closes #18168.

docs/changes.txt

@@ -175,6 +175,7 @@ wxOSX:
 - supporting native image formst like NSImage and UIImage in wxBitmap
 - native implementation for wxStaticBitmap for correct rendering of template images
 - Fill column value in wxEVT_DATAVIEW_ITEM_ACTIVATED events (Igor Korot).
+- Make wxFrame::EnableFullScreenView() work under macOS 10.11+ (Andy Robinson).
 
 wxQt:
 

src/osx/cocoa/nonownedwnd.mm

@@ -1092,10 +1092,18 @@ bool wxNonOwnedWindowCocoaImpl::EnableFullScreenView(bool enable)
     if (enable)
     {
         collectionBehavior |= NSWindowCollectionBehaviorFullScreenPrimary;
+        collectionBehavior &= ~NSWindowCollectionBehaviorFullScreenAuxiliary;
     }
     else
     {
+        // Note that just turning "Full Screen Primary" is not enough, the
+        // window would still be made full screen when the green button in the
+        // title bar is pressed, and we need to explicitly turn on the "Full
+        // Screen Auxiliary" style to prevent this from happening. This works,
+        // at least under 10.11 and 10.14, even though it's not really clear
+        // from the documentation that it should.
         collectionBehavior &= ~NSWindowCollectionBehaviorFullScreenPrimary;
+        collectionBehavior |= NSWindowCollectionBehaviorFullScreenAuxiliary;
     }
     [m_macWindow setCollectionBehavior: collectionBehavior];