Index: src/OFMutableArray.h
==================================================================
--- src/OFMutableArray.h
+++ src/OFMutableArray.h
@@ -13,11 +13,15 @@
 
 /**
  * The OFMutableArray class is a class for storing, adding and removing objects
  * in an array.
  */
-@interface OFMutableArray: OFArray {}
+@interface OFMutableArray: OFArray
+{
+	unsigned long mutations;
+}
+
 /**
  * Adds an object to the OFArray.
  *
  * \param obj An object to add
  */

Index: src/OFMutableArray.m
==================================================================
--- src/OFMutableArray.m
+++ src/OFMutableArray.m
@@ -38,19 +38,23 @@
 - addObject: (OFObject*)obj
 {
 	[array addItem: &obj];
 	[obj retain];
 
+	mutations++;
+
 	return self;
 }
 
 - addObject: (OFObject*)obj
     atIndex: (size_t)index
 {
 	[array addItem: &obj
 	       atIndex: index];
 	[obj retain];
+
+	mutations++;
 
 	return self;
 }
 
 - replaceObject: (OFObject*)old
@@ -108,11 +112,14 @@
 	size_t i, count = [array count];
 
 	for (i = 0; i < count; i++) {
 		if ([objs[i] isEqual: obj]) {
 			OFObject *obj = objs[i];
+
 			[array removeItemAtIndex: i];
+			mutations++;
+
 			[obj release];
 		}
 	}
 
 	return self;
@@ -124,10 +131,12 @@
 	size_t i, count = [array count];
 
 	for (i = 0; i < count; i++) {
 		if (objs[i] == obj) {
 			[array removeItemAtIndex: i];
+			mutations++;
+
 			[obj release];
 		}
 	}
 
 	return self;
@@ -151,10 +160,11 @@
 				 withSize: sizeof(OFObject*)];
 	memcpy(copy, objs + (count - nobjects), nobjects * sizeof(OFObject*));
 
 	@try {
 		[array removeNItems: nobjects];
+		mutations++;
 
 		for (i = 0; i < nobjects; i++)
 			[copy[i] release];
 	} @finally {
 		[self freeMemory: copy];
@@ -177,10 +187,11 @@
 	memcpy(copy, objs + index, nobjects * sizeof(OFObject*));
 
 	@try {
 		[array removeNItems: nobjects
 			    atIndex: index];
+		mutations++;
 
 		for (i = 0; i < nobjects; i++)
 			[copy[i] release];
 	} @finally {
 		[self freeMemory: copy];