PX4 config: Insist on correct throttle position before accepting RC config end

src/ui/QGCPX4VehicleConfig.cc

@@ -422,22 +422,31 @@ void QGCPX4VehicleConfig::setTrimPositions()
         rcTrim[i] = 1500;
     }
 
+    bool throttleDone = false;
+
+    while (!throttleDone) {
         // Set trim to min if stick is close to min
         if (abs(rcValue[throttleMap] - rcMin[throttleMap]) < 100) {
             rcTrim[throttleMap] = rcMin[throttleMap];   // throttle
+            throttleDone = true;
         }
         // Set trim to max if stick is close to max
         else if (abs(rcValue[throttleMap] - rcMax[throttleMap]) < 100) {
             rcTrim[throttleMap] = rcMax[throttleMap];   // throttle
+            throttleDone = true;
         }
-    else  {
+        else
+        {
             // Reject
             QMessageBox warnMsgBox;
             warnMsgBox.setText(tr("Throttle Stick Trim Position Invalid"));
-        warnMsgBox.setInformativeText(tr("The throttle stick is not in the min position. Please set it to the minimum value"));
+            warnMsgBox.setInformativeText(tr("The throttle stick is not in the min position. Please set it to the zero throttle position and then click OK."));
             warnMsgBox.setStandardButtons(QMessageBox::Ok);
             warnMsgBox.setDefaultButton(QMessageBox::Ok);
             (void)warnMsgBox.exec();
+            // wait long enough to get some data
+            QGC::SLEEP::msleep(500);
+        }
     }
 
     // Set trim for roll, pitch, yaw, throttle