Some random small stuff packed in one commit:

- Moved a couple of undo_push_mesh after the action has been confirmed (mainly bevel, merge and mirror)

- Split mirror in two functions, interface and functionality

- Simplified the code of the merge function

source/blender/src/edit.c

@@ -1180,22 +1180,18 @@ void mergemenu(void)
 
 	event = pupmenu("MERGE %t|At Center%x1|At Cursor%x2");
 
-	switch (event) {
+	if (event==-1) return; /* Return if the menu is closed without any choices */
+
+	undo_push_mesh("Merge"); /* The action has been confirmed, push the mesh down the undo pipe */
+
+	if (event==1) 
+		snap_to_center(); /*Merge at Center*/
+	else
+		snap_sel_to_curs(); /*Merge at Cursor*/
 
-	    case 1: /*Merge at center of selection*/
-		    snap_to_center();
 	notice("Removed: %d", removedoublesflag(1, doublimit));
 	allqueue(REDRAWVIEW3D, 0);
 	countall();
-		    break;
-	    case 2: /*Merge at Cursor*/
-		    snap_sel_to_curs();
-		    notice("Removed: %d", removedoublesflag(1, doublimit));
-		    allqueue(REDRAWVIEW3D, 0);
-		    countall();
-		    break;
-	}
-
 }
 
 void delete_context_selected(void) {

source/blender/src/editmesh.c

@@ -7742,6 +7742,7 @@ void undo_menu_mesh(void)
 }
 
 /******************* BEVEL CODE STARTS HERE ********************/
+
 void bevel_displace_vec(float *midvec, float *v1, float *v2, float *v3, float d, float no[3])
 {
 	float a[3], c[3], n_a[3], n_c[3], mid[3], ac, ac2, fac;
@@ -8147,7 +8148,9 @@ void bevel_mesh(float bsize, int allfaces)
 	/* tag all faces for shrink*/
 	evl= G.edvl.first;
 	while (evl) {
-		if (vlakselectedAND(evl, 1)||allfaces) evl->f1= 2;
+		if (vlakselectedAND(evl, 1)||allfaces) {
+			evl->f1= 2;
+		}
 		evl= evl->next;
 	}
 
@@ -8524,6 +8527,7 @@ void bevel_menu()
 		}	
 	}
 	if (Canceled==0) {
+		undo_push_mesh("Bevel");
 		bevel_mesh_recurs(drawd/fac, recurs, 1);
 		righthandfaces(1);
 	}

source/blender/src/editobject.c

@@ -1577,7 +1577,6 @@ void special_editmenu(void)
 			subdivideflag(1, 0.0, editbutflag | B_SMOOTH);
 			break;
 		case 4:
-			undo_push_mesh("Merge");
 			mergemenu();
 			break;
 		case 5:
@@ -1602,7 +1601,6 @@ void special_editmenu(void)
 			vertexsmooth();
 			break;
 		case 11:
-			undo_push_mesh("Bevel");
 			bevel_menu();
 			break;
 		}		
@@ -6751,19 +6749,14 @@ void make_displists_by_obdata(void *obdata) {
 /* ******************************************************************** */
 /* Mirror function in Edit Mode */
 
-
-void mirrormenu(void){
-	short mode = 0, axis, a;
+void mirror(short mode) {
+	short axis, a;
 	float mat[3][3], imat[3][3], min[3], max[3];
 	TransVert *tv;
-	mode=pupmenu("Mirror Axis %t|Global X%x1|       Y%x2|       Z%x3|Local X%x4|      Y%x5|      Z%x6|View X%x7|     Y%x8|     Z%x9|");
-
-	if (G.obedit==0) return;
-	if (mode==-1) return;
 
 	make_trans_verts(min, max, 0);
 	Mat3CpyMat4(mat, G.obedit->obmat);
-	// Inverting the matrix explicitly, since a 4x4 inverse is not always the same
+	// Inverting the matrix explicitly, since the inverse is not always correct (then why the heck are we keeping it!)
 	Mat3Inv(imat, mat);
 
 	tv = transvmain;
@@ -6832,7 +6825,7 @@ void mirrormenu(void){
 		float viewmat[3][3], iviewmat[3][3];
 
 		Mat3CpyMat4(viewmat, G.vd->viewmat);
-	// Inverting the matrix explicitly, since a 4x4 inverse is not always the same
+	// Inverting the matrix explicitly
 		Mat3Inv(iviewmat, viewmat);
 
 		// axis is mode with an offset
@@ -6883,3 +6876,18 @@ void mirrormenu(void){
 
 	tottrans= 0;
 }
+
+void mirrormenu(void){
+	short mode = 0;
+
+	if (G.obedit==0) return;
+
+	mode=pupmenu("Mirror Axis %t|Global X%x1|       Y%x2|       Z%x3|Local X%x4|      Y%x5|      Z%x6|View X%x7|     Y%x8|     Z%x9|");
+
+	if (mode==-1) return; /* return */
+
+	if(G.obedit->type==OB_MESH) undo_push_mesh("Mirror"); /* If it's a mesh, push it down the undo pipe */
+
+	mirror(mode); /* separating functionality from interface | call*/
+}
+

source/blender/src/space.c

@@ -1130,21 +1130,13 @@ void winqreadview3dspace(ScrArea *sa, void *spacedata, BWinEvent *evt)
 				if(G.obedit){
 					if(G.qual==LR_ALTKEY) {
 						if(G.obedit->type==OB_MESH) {
-							undo_push_mesh("Merge");
 							mergemenu();
-								
 							makeDispList(G.obedit);
 						}
 					}
 					else if((G.qual==0)) {
-						if(G.obedit->type==OB_MESH) {
-							undo_push_mesh("Mirror");
 						mirrormenu();
 					}
-						else {
-							mirrormenu();
-						}
-					}
 				}
 				else if((G.qual==0)){
 				     movetolayer();