fixed add app entry button not working

Author: sharpjd

GPUPrefSwitcherGUI/MainForm.cs

@@ -476,6 +476,8 @@ private void AddEntryButton_Click(object sender, EventArgs e)
 
                         AppEntry newAppEntry = GetDefaultAppEntry(newPath) with { PendingAddToRegistry = true };
 
+                        appEntrySaver.CurrentAppEntries.Add(newAppEntry);
+
                         UpdateGrid();
                         UpdateActionButtons();