ResizableWindow: resizable corner is hidden when using native titlebar

When helping a fellow dev on the discord server we found out, that the resizerCorner is hidden when the native titlebar is used.
The reason is the condition here:

Removing the last condition || isUsingNativeTitleBar() avoids this problem, but I assume it is there, because the OS already allows resizing by dragging the border.

It might need a special case when the useBottomRightCornerResizer was selected…

Just, I stumbled across the same thing.

According to

ResizableWindow::setResizable (const bool shouldBeResizable,
                                    const bool useBottomRightCornerResizer)

…the ability to resize is independent of whether a corner-resized exists. So this might be a bug?

Technically you can use any other kind of UI element to resize, e.g. some have a fixed number of sizes they support. The user can then select from those with a combobox.

And maybe they hoped Apple would fix the missing resizing from the plugin border, which works only for apple’s own plugins. I wouldn’t put much hope in that, since they focus now on AUv3 and they didn’t bother for 10 years…

So telling the host the UI can be resized and adding the corner dragger should probably remain separate things.