Make sure that the script editor is the 3rd tab. I implemented the simplest solution I could think for now. If more control is needed in the future, EditorPlugins will likely need a priority queue (or some different, more generic solution).

editor/editor_plugin.h

@@ -330,6 +330,19 @@ public:
 		ERR_FAIL_COND(creation_func_count >= MAX_CREATE_FUNCS);
 		creation_funcs[creation_func_count++] = p_func;
 	}
+
+	template <class T>
+	static void add_by_type_front() {
+		ERR_FAIL_COND(creation_func_count >= MAX_CREATE_FUNCS);
+
+		for (int i = creation_func_count - 1; i >= 0; --i) {
+			creation_funcs[i + 1] = creation_funcs[i];
+		}
+
+		++creation_func_count;
+
+		creation_funcs[0] = creator<T>;
+	}
 };
 
 #endif

editor_modules/editor_code_editor/register_types.cpp

@@ -25,7 +25,7 @@ void register_editor_code_editor_types(ModuleRegistrationLevel p_level) {
 
 #ifdef TOOLS_ENABLED
 	if (p_level == MODULE_REGISTRATION_LEVEL_EDITOR) {
-		EditorPlugins::add_by_type<EditorScriptEditorPlugin>();
+		EditorPlugins::add_by_type_front<EditorScriptEditorPlugin>();
 	}
 #endif
 }