### Eclipse Workspace Patch 1.0
#P org.eclipse.swt
Index: Eclipse SWT Custom Widgets/common/org/eclipse/swt/custom/CTabFolder.java
===================================================================
RCS file: /cvsroot/eclipse/org.eclipse.swt/Eclipse SWT Custom Widgets/common/org/eclipse/swt/custom/CTabFolder.java,v
retrieving revision 1.289
diff -u -r1.289 CTabFolder.java
--- Eclipse SWT Custom Widgets/common/org/eclipse/swt/custom/CTabFolder.java	2 Apr 2009 22:35:06 -0000	1.289
+++ Eclipse SWT Custom Widgets/common/org/eclipse/swt/custom/CTabFolder.java	3 Apr 2009 14:07:08 -0000
@@ -202,6 +202,7 @@
 	// on Resize
 	Point oldSize;
 	Font oldFont;
+	CTabFolderPageManager pageManager;
 	
 	// internal constants
 	static final int DEFAULT_WIDTH = 64;
@@ -555,6 +556,12 @@
 		color.dispose();
 	}
 }
+boolean canLeaveThePage(int oldIndex, int newIndex) {
+    if (pageManager != null) {
+	return pageManager.canLeaveThePage(oldIndex, newIndex);
+    }
+    return true;
+}
 /*
 * This class was not intended to be subclassed but this restriction
 * cannot be enforced without breaking backward compatibility.
@@ -1416,6 +1423,16 @@
 	checkWidget();
 	return mru;
 }
+/**
+ * Returns the Page Manager that is used by the <code>CTabfolder</code> before switching between tab-items.
+ * 
+ * @return the tabfolder's Page Manager, or null if no Page Manager has been set.
+ * 
+ * @since 
+ */
+public CTabFolderPageManager getPageManager() {
+   return pageManager;
+}
 int getRightItemEdge (){
 	int x = getSize().x - borderRight - 3;
 	if (showMin) x -= BUTTON_SIZE;
@@ -3185,6 +3202,28 @@
 	}
 }
 /**
+ * Sets the Page Manager that will be used to by the <code>CTabFolder</code> before 
+ * switching between tab-items. 
+ * The Page Manager should implement the <code>CTabFolderPageManager</code> and 
+ * implement the method <code>canLeaveThePage</code>.
+ * 
+ * @param pageManager the Page Manager for the <code>CTabFolder</code>
+ * 
+ * @exception IllegalArgumentException <ul>
+ *    <li>ERROR_INVALID_RANGE - if the index is out of range</li>
+ * </ul>
+ * 
+ * @exception SWTException <ul>
+ *    <li>ERROR_THREAD_INVALID_ACCESS when called from the wrong thread</li>
+ *    <li>ERROR_WIDGET_DISPOSED when the widget has been disposed</li>
+ * </ul>
+ * 
+ * @since
+ */
+public void setPageManager(CTabFolderPageManager pageManager) {
+    	this.pageManager = pageManager;
+}
+/**
  * Set the selection to the tab at the specified item.
  * 
  * @param item the tab item to be selected
@@ -3222,7 +3261,12 @@
 		showItem(selection);
 		return;
 	}
-	
+	/* 
+	 * If the user has set a Page Manager for the previously selected tab-item,
+	 * then call the canLeaveThePage() method to do any validations in the Page Manager,
+	 * before switching the tab. Don't change the tab selection if validation fails.
+	 */
+	if (selectedIndex != -1 && !canLeaveThePage(selectedIndex, index)) return;
 	int oldIndex = selectedIndex;
 	selectedIndex = index;
 	if (oldIndex != -1) {
Index: Eclipse SWT Custom Widgets/common/org/eclipse/swt/custom/CTabFolderPageManager.java
===================================================================
RCS file: Eclipse SWT Custom Widgets/common/org/eclipse/swt/custom/CTabFolderPageManager.java
diff -N Eclipse SWT Custom Widgets/common/org/eclipse/swt/custom/CTabFolderPageManager.java
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ Eclipse SWT Custom Widgets/common/org/eclipse/swt/custom/CTabFolderPageManager.java	1 Jan 1970 00:00:00 -0000
@@ -0,0 +1,25 @@
+package org.eclipse.swt.custom;
+
+/**
+ * This is an Interface which provides a mechanism to use a Page Manager for a <code>CTabItem</code>.
+ * The Page Manager can be used to do any validations as required by the user while switching between tab-items.
+ * The Page Manager should implement the method <code>canLeaveThePage</code>.
+ */
+
+public interface CTabFolderPageManager {
+    /**
+     * This method is called before changing the tab selection of the <code>CTabFolder</code>
+     *  
+     * @param oldIndex is index of tab selected in the <code>CTabFolder</code>
+     * @param newIndex is index of the tab that will be selected if this method returns true
+     * 
+     * @return <ul>
+     * <li><code>true</code> if the tab selection should be changed from <code>oldIndex</code>
+     * to <code>newIndex</code></li>
+     * <li><code>false</code> if the tab selection should not be changed.</li>
+     * </ul>
+     * 
+     * @since
+     */
+    public boolean canLeaveThePage(int oldIndex, int newIndex);
+}