const static char* WDG_DOUBLEVALUE_EDITOR = "doublevalue_editor";
const static char* WDG_FILE_SELECTOR= "file_selector";
const static char* WDG_EXPR_EDITOR = "expr_editor";
+const static char* WDG_PLACE_HOLDER = "placeholder";
+
// Containers
const static char* WDG_GROUP = "groupbox";
const static char* WDG_CHECK_GROUP = "check_groupbox";