UI defaults:

- moved some common properties from FlatLightLaf.properties and FlatDarkLaf.properties to FlatLaf.properties
- use color functions for more properties

flatlaf-testing/dumps/uidefaults/FlatDarkLaf_1.8.0_202.txt

@@ -1246,7 +1246,7 @@ Tree.editorBorder              [lazy] 1,1,1,1  false    com.formdev.flatlaf.ui.F
 Tree.expandedIcon              [lazy] 11,11    com.formdev.flatlaf.icons.FlatTreeExpandedIcon [UI]
 Tree.font                      [active] $defaultFont [UI]
 Tree.foreground                #bbbbbb    javax.swing.plaf.ColorUIResource [UI]
-Tree.hash                      #505355    javax.swing.plaf.ColorUIResource [UI]
+Tree.hash                      #515657    javax.swing.plaf.ColorUIResource [UI]
 Tree.icon.closedColor          #adadad    javax.swing.plaf.ColorUIResource [UI]
 Tree.icon.collapsedColor       #adadad    javax.swing.plaf.ColorUIResource [UI]
 Tree.icon.expandedColor        #adadad    javax.swing.plaf.ColorUIResource [UI]

flatlaf-testing/src/main/resources/com/formdev/flatlaf/testing/FlatTestLaf.properties

@@ -32,6 +32,12 @@
 @cellFocusColor = #f00
 @icon = #afafaf
 
+# for buttons within components (e.g. combobox or spinner)
+@buttonArrowColor = #666
+@buttonDisabledArrowColor = #ABABAB
+@buttonHoverArrowColor = #f00
+@buttonPressedArrowColor = #00f
+
 @dropCellBackground = #f00
 @dropCellForeground = #0f0
 @dropLineColor = #00f
@@ -118,10 +124,6 @@ CheckBox.icon.pressedBackground = #FFC800
 ComboBox.background = #fff
 ComboBox.buttonBackground = #f0f0f0
 ComboBox.buttonEditableBackground = #ccc
-ComboBox.buttonArrowColor = #666
-ComboBox.buttonDisabledArrowColor = #ABABAB
-ComboBox.buttonHoverArrowColor = #f00
-ComboBox.buttonPressedArrowColor = #00f
 
 
 #---- Component ----