Attempt at working around another 10.14 drawing issue (#3271)

Frameworks/PSMTabBar/PSMRolloverButton.h

@@ -16,19 +16,19 @@
}

// the regular image
- (void)setUsualImage:(nullable NSImage *)newImage;
- (nullable NSImage *)usualImage;
- (void)setUsualImage:(NSImage *)newImage;
- (NSImage *)usualImage;

// the rollover image
- (void)setRolloverImage:(nullable NSImage *)newImage;
- (nullable NSImage *)rolloverImage;
- (void)setRolloverImage:(NSImage *)newImage;
- (NSImage *)rolloverImage;

// tracking rect for mouse events
- (void)rolloverFrameDidChange:(nonnull NSNotification *)notification;
- (void)rolloverFrameDidChange:(NSNotification *)notification;
- (void)addTrackingRect;
- (void)removeTrackingRect;

- (void)mouseEntered:(nullable NSEvent *)event;
- (void)mouseExited:(nullable NSEvent *)event;
- (void)mouseEntered:(NSEvent *)event;
- (void)mouseExited:(NSEvent *)event;

@end

Frameworks/PSMTabBar/PSMRolloverButton.m

@@ -118,15 +118,15 @@ - (void)removeTrackingRect
}

// override for rollover effect
- (void)mouseEntered:(nullable NSEvent *)event
- (void)mouseEntered:(NSEvent *)event
{
    // set rollover image
    [self setImage:_rolloverImage];

	[super mouseEntered:event];
}

- (void)mouseExited:(nullable NSEvent *)event
- (void)mouseExited:(NSEvent *)event
{
    // restore usual image
	[self setImage:_usualImage];