[FancyZones] Open window on active monitor (#4361)

* Initial design for opening window on active monitor

* Perform entire handling in DPI unaware thread

* Codestyle improvement

* Improve resizing mechanism and optimise code a bit

* Remove unneeded code, make simple helper functions inline

* Make this feature configurable

* Code optimization, improve positioning for some applications

* Retry positioning for certain applications

* Improve readability

* Address PR comments: Minor code style improvements

* Remove retries in custom positioning

* Position new toggle in settings menu

src/core/Microsoft.PowerToys.Settings.UnitTest/ViewModelTests/FancyZones.cs

@@ -194,6 +194,23 @@ namespace ViewModelTests
             viewModel.AppLastZoneMoveWindows = true;
         }
 
+        public void OpenWindowOnActiveMonitor_ShouldSetValue2True_WhenSuccessful()
+        {
+            // arrange
+            FancyZonesViewModel viewModel = new FancyZonesViewModel();
+            Assert.IsFalse(viewModel.OpenWindowOnActiveMonitor); // check if value was initialized to false.
+
+            // Assert
+            ShellPage.DefaultSndMSGCallback = msg =>
+            {
+                FancyZonesSettingsIPCMessage snd = JsonSerializer.Deserialize<FancyZonesSettingsIPCMessage>(msg);
+                Assert.IsTrue(snd.Powertoys.FancyZones.Properties.FancyzonesOpenWindowOnActiveMonitor.Value);
+            };
+
+            // act
+            viewModel.OpenWindowOnActiveMonitor = true;
+        }
+
         [TestMethod]
         public void RestoreSize_ShouldSetValue2True_WhenSuccessful()
         {