--- a/src/tools/uic/uic.cpp	2020-05-27 16:36:23.609764074 +0200
+++ b/src/tools/uic/uic.cpp	2020-05-27 16:37:57.553574102 +0200
@@ -323,7 +323,8 @@
 
 bool Uic::isButton(const QString &className) const
 {
-    return customWidgetsInfo()->extends(className, QLatin1String("QRadioButton"))
+    return customWidgetsInfo()->extends(className, QLatin1String("QAbstractButton"))
+        || customWidgetsInfo()->extends(className, QLatin1String("QRadioButton"))
         || customWidgetsInfo()->extends(className, QLatin1String("QToolButton"))
         || customWidgetsInfo()->extends(className, QLatin1String("QCheckBox"))
         || customWidgetsInfo()->extends(className, QLatin1String("QPushButton"))