[Companion][AppPreferencesDialog] If not ALLOW_NIGHTLY_BUILDS then either hide nightly channel option, or if user already has it selected then display a warning (in case they also have nightly installed in parallel).

companion/src/apppreferencesdialog.cpp

@@ -170,10 +170,17 @@ void AppPreferencesDialog::initSettings()
     ui->snapshotPath->setDisabled(true);
     ui->snapshotPathButton->setDisabled(true);
   }
+
 #if !defined(ALLOW_NIGHTLY_BUILDS)
-  // TODO should we gray out nightly builds here?
+  // remove nightly version option entirely unless it's the current one (because user might have nightly version also installed)
+  if (g.OpenTxBranch() != AppData::BRANCH_NIGHTLY_UNSTABLE)
+    ui->OpenTxBranch->removeItem(2);
+  // if it's already selected, add a warning message
+  else
+    ui->updatesLayout->addWidget(new QLabel("<font color='red'>" % tr("Note: Nightly builds are not available in this version, Release/RC update channel will be used.") % "</font>", this));
 #endif
   ui->OpenTxBranch->setCurrentIndex(g.OpenTxBranch());
+
   ui->autoCheckCompanion->setChecked(g.autoCheckApp());
   ui->autoCheckFirmware->setChecked(g.autoCheckFw());
   ui->showSplash->setChecked(g.showSplash());

companion/src/apppreferencesdialog.ui

@@ -767,8 +767,8 @@ Mode 4:
           <number>6</number>
          </property>
          <item row="7" column="1">
-          <layout class="QGridLayout" name="gridLayout_6">
-           <item row="0" column="0">
+          <layout class="QVBoxLayout" name="updatesLayout">
+           <item>
             <widget class="QCheckBox" name="autoCheckFirmware">
              <property name="text">
               <string>Automatic check for OpenTX firmware updates</string>
@@ -778,7 +778,7 @@ Mode 4:
              </property>
             </widget>
            </item>
-           <item row="1" column="0">
+           <item>
             <widget class="QCheckBox" name="autoCheckCompanion">
              <property name="text">
               <string>Automatic check for Companion updates</string>
@@ -788,7 +788,7 @@ Mode 4:
              </property>
             </widget>
            </item>
-           <item row="2" column="0">
+           <item>
             <widget class="QComboBox" name="OpenTxBranch">
              <property name="sizePolicy">
               <sizepolicy hsizetype="Expanding" vsizetype="Fixed">