disable max button if an amount has been typed

gui/qt/main_window.py

@@ -1065,7 +1065,12 @@ class ElectrumWindow(QMainWindow, MessageBoxMixin, PrintError):
         self.amount_e.shortcut.connect(self.spend_max)
         self.payto_e.textChanged.connect(self.update_fee)
         self.amount_e.textEdited.connect(self.update_fee)
-        self.amount_e.textEdited.connect(self.reset_max)
+
+        def reset_max(t):
+            self.is_max = False
+            self.max_button.setEnabled(not bool(t))
+        self.amount_e.textEdited.connect(reset_max)
+        self.fiat_send_e.textEdited.connect(reset_max)
 
         def entry_changed():
             text = ""
@@ -1113,9 +1118,6 @@ class ElectrumWindow(QMainWindow, MessageBoxMixin, PrintError):
         self.is_max = True
         self.do_update_fee()
 
-    def reset_max(self):
-        self.is_max = False
-
     def update_fee(self):
         self.require_fee_update = True