diff --git a/source/blender/editors/interface/interface_query.c b/source/blender/editors/interface/interface_query.c
index e08b13f65d4..457d01c5dc8 100644
--- a/source/blender/editors/interface/interface_query.c
+++ b/source/blender/editors/interface/interface_query.c
@@ -139,7 +139,17 @@ bool ui_but_has_array_value(const uiBut *but)
 
 bool UI_but_is_tool(const uiBut *but)
 {
-  return but->optype && but->optype->is_tool_button;
+  /* very evil! */
+  if (but->optype != NULL) {
+    static wmOperatorType *ot = NULL;
+    if (ot == NULL) {
+      ot = WM_operatortype_find("WM_OT_tool_set_by_id", false);
+    }
+    if (but->optype == ot) {
+      return true;
+    }
+  }
+  return false;
 }
 
 bool UI_but_has_tooltip_label(const uiBut *but)
diff --git a/source/blender/windowmanager/WM_types.h b/source/blender/windowmanager/WM_types.h
index 0cf8b9c89f6..15ad8cbedc4 100644
--- a/source/blender/windowmanager/WM_types.h
+++ b/source/blender/windowmanager/WM_types.h
@@ -773,8 +773,6 @@ typedef struct wmOperatorType {
   /** Flag last for padding */
   short flag;
 
-  /** Is the operator used by tool buttons, hack for fast checking. */
-  bool is_tool_button;
 } wmOperatorType;
 
 /**
diff --git a/source/blender/windowmanager/intern/wm_operator_type.c b/source/blender/windowmanager/intern/wm_operator_type.c
index 394efc856e3..e3fe8892515 100644
--- a/source/blender/windowmanager/intern/wm_operator_type.c
+++ b/source/blender/windowmanager/intern/wm_operator_type.c
@@ -20,8 +20,6 @@
  * Operator Registry.
  */
 
-#include <string.h>
-
 #include "MEM_guardedalloc.h"
 
 #include "CLG_log.h"
@@ -129,9 +127,6 @@ static void wm_operatortype_append__end(wmOperatorType *ot)
       ot->srna, ot->name, ot->description ? ot->description : UNDOCUMENTED_OPERATOR_TIP);
   RNA_def_struct_identifier(&BLENDER_RNA, ot->srna, ot->idname);
 
-  /* A hack for efficiently detecting buttons with this specific operator. */
-  ot->is_tool_button = STREQ(ot->idname, "WM_OT_tool_set_by_id");
-
   BLI_ghash_insert(global_ops_hash, (void *)ot->idname, ot);
 }