qt seed dialog fixes

for xpub, reenable show qr code option (fixes #4307)
set to read-only when editing capability is not intentional
allow tab to auto-complete

gui/qt/installwizard.py

@@ -534,7 +534,7 @@ class InstallWizard(QDialog, MessageBoxMixin, BaseWizard):
             _("Please share it with your cosigners.")
         ])
         vbox = QVBoxLayout()
-        layout = SeedLayout(xpub, title=msg, icon=False)
+        layout = SeedLayout(xpub, title=msg, icon=False, for_seed_words=False)
         vbox.addLayout(layout.layout())
         self.exec_layout(vbox, _('Master Public Key'))
         return None

gui/qt/seed_dialog.py

@@ -88,17 +88,24 @@ class SeedLayout(QVBoxLayout):
         self.is_ext = cb_ext.isChecked() if 'ext' in self.options else False
         self.is_bip39 = cb_bip39.isChecked() if 'bip39' in self.options else False
 
-    def __init__(self, seed=None, title=None, icon=True, msg=None, options=None, is_seed=None, passphrase=None, parent=None):
+    def __init__(self, seed=None, title=None, icon=True, msg=None, options=None,
+                 is_seed=None, passphrase=None, parent=None, for_seed_words=True):
         QVBoxLayout.__init__(self)
         self.parent = parent
         self.options = options
         if title:
             self.addWidget(WWLabel(title))
-        self.seed_e = CompletionTextEdit()
+        if seed:  # "read only", we already have the text
-        if seed:
+            if for_seed_words:
+                self.seed_e = ButtonsTextEdit()
+            else:  # e.g. xpub
+                self.seed_e = ShowQRTextEdit()
+            self.seed_e.setReadOnly(True)
             self.seed_e.setText(seed)
-        else:
+        else:  # we expect user to enter text
-            self.seed_e.setTabChangesFocus(True)
+            assert for_seed_words
+            self.seed_e = CompletionTextEdit()
+            self.seed_e.setTabChangesFocus(False)  # so that tab auto-completes
             self.is_seed = is_seed
             self.saved_is_seed = self.is_seed
             self.seed_e.textChanged.connect(self.on_edit)