Compute fg and bg colors for setEditable for StyledText

This commit adds the foreground and background color computation for
setEditable. Earlier this was handled only for setEnabled. This commit
also adds a different foreground and background color for StyledText
when background is not editable.

Fixes :#3132

Author: elsazac

bundles/org.eclipse.swt/Eclipse SWT Custom Widgets/common/org/eclipse/swt/custom/StyledText.java

@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (c) 2000, 2021 IBM Corporation and others.
+ * Copyright (c) 2000, 2026 IBM Corporation and others.
  *
  * This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License 2.0
@@ -149,7 +149,7 @@ public class StyledText extends Canvas {
 	/** False iff the widget is disabled */
 	boolean enabled = true;
 	/** True iff the widget is in the midst of being enabled or disabled */
-	boolean insideSetEnableCall;
+	boolean insideUpdateColorsCall;
 	Clipboard clipboard;
 	int clickCount;
 	int autoScrollDirection = SWT.NULL;	// the direction of autoscrolling (up, down, right, left)
@@ -8278,7 +8278,7 @@ public void setBackground(Color color) {
 	boolean backgroundDisabled = false;
 	if (!this.enabled && color == null) {
 		if (background != null) {
-			Color disabledBg = getDisplay().getSystemColor(SWT.COLOR_TEXT_DISABLED_BACKGROUND);
+			Color disabledBg = getDisplay().getSystemColor(SWT.COLOR_WIDGET_DISABLED_FOREGROUND);
 			if (background.equals(disabledBg)) {
 				return;
 			} else {
@@ -8287,11 +8287,13 @@ public void setBackground(Color color) {
 			}
 		}
 	}
-	customBackground = color != null && !this.insideSetEnableCall && !backgroundDisabled;
+	customBackground = color != null && !this.insideUpdateColorsCall && !backgroundDisabled;
 	background = color;
 	super.setBackground(color);
-	resetCache(0, content.getLineCount());
-	setCaretLocations();
+	if (content != null) {
+		resetCache(0, content.getLineCount());
+		setCaretLocations();
+	}
 	super.redraw();
 }
 /**
@@ -8772,6 +8774,35 @@ public void setDragDetect (boolean dragDetect) {
 	checkWidget ();
 	this.dragDetect = dragDetect;
 }
+
+/**
+ * Applies foreground and background colors based on the control's state.
+ * Custom foreground and background settings are preserved and not overridden.
+ *
+ * @param enabled  {@code true} if the control is enabled; {@code false} otherwise
+ * @param editable {@code true} if the control is editable; {@code false} otherwise
+ *
+ */
+private void updateColors(boolean enabled, boolean editable) {
+	this.insideUpdateColorsCall = true;
+	Display display = getDisplay();
+	try {
+		if (enabled && editable) {
+			if (!customBackground) setBackground(display.getSystemColor(SWT.COLOR_LIST_BACKGROUND));
+			if (!customForeground) setForeground(display.getSystemColor(SWT.COLOR_LIST_FOREGROUND));
+		} else if(!enabled) {
+			if (!customBackground) setBackground(display.getSystemColor(SWT.COLOR_WIDGET_DISABLED_FOREGROUND));
+			if (!customForeground) setForeground(display.getSystemColor(SWT.COLOR_DARK_GRAY));
+		} else if(!editable) {
+			if (!customBackground) setBackground(display.getSystemColor(SWT.COLOR_WIDGET_DISABLED_FOREGROUND));
+			if (!customForeground) setForeground(display.getSystemColor(SWT.COLOR_LIST_FOREGROUND));
+		}
+	}
+	finally {
+		this.insideUpdateColorsCall = false;
+	}
+}
+
 /**
  * Sets whether the widget content can be edited.
  *
@@ -8785,28 +8816,13 @@ public void setDragDetect (boolean dragDetect) {
 public void setEditable(boolean editable) {
 	checkWidget();
 	this.editable = editable;
+	updateColors(this.enabled, this.editable);
 }
 @Override
 public void setEnabled(boolean enabled) {
 	super.setEnabled(enabled);
-	Display display = getDisplay();
 	this.enabled = enabled;
-	this.insideSetEnableCall = true;
-	try {
-		if (enabled && editable) {
-			if (!customBackground) setBackground(display.getSystemColor(SWT.COLOR_LIST_BACKGROUND));
-			if (!customForeground) setForeground(display.getSystemColor(SWT.COLOR_LIST_FOREGROUND));
-		} else if(!enabled) {
-			if (!customBackground) setBackground(display.getSystemColor(SWT.COLOR_TEXT_DISABLED_BACKGROUND));
-			if (!customForeground) setForeground(display.getSystemColor(SWT.COLOR_WIDGET_DISABLED_FOREGROUND));
-		} else if(!editable) {
-			if (!customBackground) setBackground(display.getSystemColor(SWT.COLOR_TEXT_DISABLED_BACKGROUND));
-			if (!customForeground) setForeground(display.getSystemColor(SWT.COLOR_LIST_FOREGROUND));
-		}
-	}
-	finally {
-		this.insideSetEnableCall = false;
-	}
+	updateColors(this.enabled, this.editable);
 }
 
 @Override
@@ -8873,7 +8889,7 @@ public void setForeground(Color color) {
 	boolean foregroundDisabled = false;
 	if (!this.enabled && color == null) {
 		if (foreground != null) {
-			Color disabledFg = getDisplay().getSystemColor(SWT.COLOR_WIDGET_DISABLED_FOREGROUND);
+			Color disabledFg = getDisplay().getSystemColor(SWT.COLOR_DARK_GRAY);
 			if (foreground.equals(disabledFg)) {
 				return;
 			} else {
@@ -8882,11 +8898,13 @@ public void setForeground(Color color) {
 			}
 		}
 	}
-	customForeground = color != null && !this.insideSetEnableCall && !foregroundDisabled;
+	customForeground = color != null && !this.insideUpdateColorsCall && !foregroundDisabled;
 	foreground = color;
 	super.setForeground(color);
-	resetCache(0, content.getLineCount());
-	setCaretLocations();
+	if (content != null) {
+		resetCache(0, content.getLineCount());
+		setCaretLocations();
+	}
 	super.redraw();
 }
 /**

tests/org.eclipse.swt.tests/JUnit Tests/org/eclipse/swt/tests/junit/Test_org_eclipse_swt_custom_StyledText.java

@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (c) 2000, 2025 IBM Corporation and others.
+ * Copyright (c) 2000, 2026 IBM Corporation and others.
  *
  * This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License 2.0
@@ -3245,8 +3245,8 @@ public void test_setDoubleClickEnabledZ(){
 @Test
 public void test_setEnabled(){
 	// Get colors
-	Color disabledBg = text.getDisplay().getSystemColor(SWT.COLOR_TEXT_DISABLED_BACKGROUND);
-	Color disabledFg = text.getDisplay().getSystemColor(SWT.COLOR_WIDGET_DISABLED_FOREGROUND);
+	Color disabledBg = text.getDisplay().getSystemColor(SWT.COLOR_WIDGET_DISABLED_FOREGROUND);
+	Color disabledFg = text.getDisplay().getSystemColor(SWT.COLOR_DARK_GRAY);
 	Color enabledBg = text.getDisplay().getSystemColor(SWT.COLOR_LIST_BACKGROUND);
 	Color enabledFg = text.getDisplay().getSystemColor(SWT.COLOR_LIST_FOREGROUND);