ToggleButton: styling selectedForeground did not work if foreground is also styled (issue #1017)

Author: DevCharly

CHANGELOG.md

@@ -4,6 +4,8 @@ FlatLaf Change Log
 ## 3.6.1-SNAPSHOT
 
 - Extras: Support JSVG 2.0.0. Minimum JSVG version is now 1.6.0. (issue #997)
+- ToggleButton: Styling `selectedForeground` did not work if `foreground` is
+  also styled. (issue #1017)
 - JideSplitButton: Fixed updating popup when switching theme. (issue #1000)
 - IntelliJ Themes: Fixed logging false errors when loading 3rd party
   `.theme.json` files. (issue #990)

flatlaf-core/src/main/java/com/formdev/flatlaf/ui/FlatButtonUI.java

@@ -381,6 +381,12 @@ protected Object applyStyleProperty( AbstractButton b, String key, Object value
 			return ((FlatHelpButtonIcon)helpButtonIcon).applyStyleProperty( key, value );
 		}
 
+		// update internal values; otherwise isCustomBackground() and isCustomForeground() would return wrong results
+		switch( key ) {
+			case "background":	background = (Color) value; break;
+			case "foreground":	foreground = (Color) value; break;
+		}
+
 		if( "iconTextGap".equals( key ) && value instanceof Integer )
 			value = UIScale.scale( (Integer) value );