SwingColorAlphaWidget: Fix icon displaying ARGB

Author: frauzufall

src/main/java/org/scijava/ui/swing/widget/SwingColorAlphaWidget.java

@@ -216,7 +216,7 @@ public void doRefresh() {
 		color = AWTColors.getColor(value);
 
 		final BufferedImage image =
-			new BufferedImage(SWATCH_WIDTH, SWATCH_HEIGHT, BufferedImage.TYPE_INT_RGB);
+			new BufferedImage(SWATCH_WIDTH, SWATCH_HEIGHT, BufferedImage.TYPE_INT_ARGB);
 		final Graphics g = image.getGraphics();
 		g.setColor(color);
 		g.fillRect(0, 0, image.getWidth(), image.getHeight());