A few bugfixes:

* #19583: Keying Sets list issues
Deleting a Keying Set (or a Keying Set Path) set the active index to 0, but that would mean that the first item would be selected but not visible.

* #19590: Keyframing properties of a modifier with more than one of it's type the property will highlight in all
- Modifiers now always have a unique name, so renaming a modifier should check that the name is unique. Most of the files changed in this commit were just to make sure that modifiers got unique names when they were created
- Modifiers path getter was wrapped a bit wrong (missing the "s around the name)

* Constraints Bugs
- Constraints renaming now also makes sure the names stay unique
- Fixed (or attempted to fix) compiler warnings about some enum declaration for distance constraint

source/blender/editors/object/object_edit.c

@@ -848,6 +848,7 @@ void special_editmenu(Scene *scene, View3D *v3d)
 								BooleanModifierData *bmd = NULL;
 								bmd = (BooleanModifierData *)modifier_new(eModifierType_Boolean);
 								BLI_addtail(&ob->modifiers, bmd);
+								modifier_unique_name(&ob->modifiers, bmd);
 								bmd->object = base_select->object;
 								bmd->modifier.mode |= eModifierMode_Realtime;
 								switch(nr){
@@ -978,9 +979,10 @@ static void object_flip_subdivison_particles(Scene *scene, Object *ob, int *set,
 			} 
 			else if(depth == 0 && *set != 0) {
 				SubsurfModifierData *smd = (SubsurfModifierData*) modifier_new(eModifierType_Subsurf);
-
+				
 				BLI_addtail(&ob->modifiers, smd);
-
+				modifier_unique_name(&ob->modifiers, smd);
+				
 				if (level!=-1) {
 					smd->levels = level;
 				}
@@ -1197,6 +1199,7 @@ static void copymenu_modifiers(Scene *scene, View3D *v3d, Object *ob)
 							nmd = modifier_new(md->type);
 							modifier_copyData(md, nmd);
 							BLI_addtail(&base->object->modifiers, nmd);
+							modifier_unique_name(&base->object->modifiers, nmd);
 						}
 
 						copy_object_particlesystems(base->object, ob);
@@ -1220,6 +1223,7 @@ static void copymenu_modifiers(Scene *scene, View3D *v3d, Object *ob)
 								
 								mdn = modifier_new(event);
 								BLI_addtail(&base->object->modifiers, mdn);
+								modifier_unique_name(&base->object->modifiers, mdn);
 
 								modifier_copyData(md, mdn);
 							}

source/blender/editors/object/object_hook.c

@@ -480,6 +480,7 @@ void add_hook(Scene *scene, View3D *v3d, int mode)
 				hmd = (HookModifierData*) modifier_new(eModifierType_Hook);
 				BLI_insertlinkbefore(&obedit->modifiers, md, hmd);
 				sprintf(hmd->modifier.name, "Hook-%s", ob->id.name+2);
+				modifier_unique_name(&obedit->modifiers, hmd);
 			}
 			else if (hmd->indexar) MEM_freeN(hmd->indexar); /* reassign, hook was set */
 		

source/blender/editors/object/object_modifier.c

@@ -76,7 +76,7 @@
 
 int ED_object_modifier_add(ReportList *reports, Scene *scene, Object *ob, int type)
 {
-	ModifierData *md;
+	ModifierData *md=NULL, *new_md=NULL;
 	ModifierTypeInfo *mti = modifierType_getInfo(type);
 
 	if(mti->flags&eModifierTypeFlag_Single) {
@@ -87,19 +87,28 @@ int ED_object_modifier_add(ReportList *reports, Scene *scene, Object *ob, int ty
 	}
 
 	if(type == eModifierType_ParticleSystem) {
+		/* don't need to worry about the new modifier's name, since that is set to the number
+		 * of particle systems which shouldn't have too many duplicates 
+		 */
 		object_add_particle_system(scene, ob);
 	}
 	else {
+		/* get new modifier data to add */
+		new_md= modifier_new(type);
+		
 		if(mti->flags&eModifierTypeFlag_RequiresOriginalData) {
 			md = ob->modifiers.first;
-
+			
 			while(md && modifierType_getInfo(md->type)->type==eModifierTypeType_OnlyDeform)
 				md = md->next;
-
-			BLI_insertlinkbefore(&ob->modifiers, md, modifier_new(type));
+			
+			BLI_insertlinkbefore(&ob->modifiers, md, new_md);
 		}
 		else
-			BLI_addtail(&ob->modifiers, modifier_new(type));
+			BLI_addtail(&ob->modifiers, new_md);
+		
+		/* make sure modifier data has unique name */
+		modifier_unique_name(&ob->modifiers, new_md);
 		
 		/* special cases */
 		if(type == eModifierType_Softbody) {
@@ -111,7 +120,7 @@ int ED_object_modifier_add(ReportList *reports, Scene *scene, Object *ob, int ty
 		else if(type == eModifierType_Collision) {
 			if(!ob->pd)
 				ob->pd= object_add_collision_fields(0);
-
+			
 			ob->pd->deflect= 1;
 			DAG_scene_sort(scene);
 		}
@@ -400,6 +409,7 @@ int ED_object_modifier_copy(ReportList *reports, Object *ob, ModifierData *md)
 	nmd = modifier_new(md->type);
 	modifier_copyData(md, nmd);
 	BLI_insertlink(&ob->modifiers, md, nmd);
+	modifier_unique_name(&ob->modifiers, nmd);
 
 	return 1;
 }