Fix issues with waypoint editing.

fix a number of regressions in the flight waypoint list by changing the
indexing and finding a work-around to blocking of signals

This PR addresses some (but not all) recently reported issues with the
waypoints screen reported in Issue #3188 . This PR was tested by:

- Changing the waypoint altitude and confirming it shows up correctly
when reloading the waypoint list window and on the map
- Adding a waypoint and confirming that it shows up immediately and
persists on reload
- Deleting a waypoint (except the first waypoint) and confirming that it
is removed immediately and persists on reload,

Known issues: first waypoint (typically hold) cannot be deleted -- still
looking into this one.

Fixes https://github.com/dcs-liberation/dcs_liberation/issues/3188.

changelog.md

@@ -43,6 +43,8 @@ Saves from 8.x are not compatible with 9.0.0.
 * **[UI]** Fixed UI bug where altering an "ahead of package" TOT offset would change the offset back to a "behind pacakge" offset.
 * **[UI]** Fixed bug where changing TOT offsets could result in flight startup times that are in the past.
 * **[UI]** Fixed odd spacing of the finance window when there were not enough items to fill the page.
+* **[UI]** Fixed regression where waypoint altitude changes in the waypoint list screen are applied to the wrong waypoint.
+* **[UI]** Fixed regression where waypoint additions in custom flight plans are not reflected until the window is reloaded. 
 
 # 8.1.0
 

qt_ui/windows/mission/flight/waypoints/QFlightWaypointList.py

@@ -53,9 +53,6 @@ class QFlightWaypointList(QTableView):
         self.setItemDelegateForColumn(1, self.altitude_editor_delegate)
 
     def update_list(self) -> None:
-        # ignore signals when updating list so on_changed does not fire
-        self.model.blockSignals(True)
-        try:
         # We need to keep just the row and rebuild the index later because the
         # QModelIndex will not be valid after the model is cleared.
         current_index = self.currentIndex().row()
@@ -90,9 +87,6 @@ class QFlightWaypointList(QTableView):
         for i in range(0, self.model.columnCount()):
             total_column_width += self.columnWidth(i) + self.lineWidth()
         self.setFixedWidth(total_column_width)
-        finally:
-            # stop ignoring signals
-            self.model.blockSignals(False)
 
     def _add_waypoint_row(
         self, row: int, flight: Flight, waypoint: FlightWaypoint
@@ -118,9 +112,13 @@ class QFlightWaypointList(QTableView):
 
     def on_changed(self) -> None:
         for i in range(self.model.rowCount()):
+            if self.model.item(i, 1) is not None:
                 altitude = self.model.item(i, 1).text()
                 altitude_feet = float(altitude)
-            self.flight.flight_plan.waypoints[i].alt = Distance.from_feet(altitude_feet)
+                # update waypoint index i+1 as rows are 1-indexed
+                self.flight.flight_plan.waypoints[i + 1].alt = Distance.from_feet(
+                    altitude_feet
+                )
 
     def tot_text(self, flight: Flight, waypoint: FlightWaypoint) -> str:
         if waypoint.waypoint_type == FlightWaypointType.TAKEOFF: