Friendlier minimum sizing for small screens for air-gapped signing functionalities, i.e. main window and transaction dialog

electrum/gui/qt/main_window.py

@@ -241,7 +241,7 @@ class ElectrumWindow(QMainWindow, MessageBoxMixin, Logger):
 
         tabs.setSizePolicy(QSizePolicy.Expanding, QSizePolicy.Expanding)
 
-        central_widget = QWidget()
+        central_widget = QScrollArea()
         vbox = QVBoxLayout(central_widget)
         vbox.setContentsMargins(0, 0, 0, 0)
         vbox.addWidget(tabs)

electrum/gui/qt/transaction_dialog.py

@@ -110,7 +110,8 @@ class BaseTxDialog(QDialog, MessageBoxMixin):
         self.prompt_if_unsaved = prompt_if_unsaved
         self.saved = False
         self.desc = desc
-        self.setMinimumWidth(1200)
+        self.setMinimumWidth(640)
+        self.resize(1200,600)
         self.set_title()
 
         self.psbt_only_widgets = []  # type: List[QWidget]