Improve selection model of list view:

* Clear selection if an empty space is clicked
* only open context menu if an item is selected

main/ui/src/main/java/org/cryptomator/ui/mainwindow/VaultListController.java

@@ -25,6 +25,8 @@ import javafx.collections.ListChangeListener;
 import javafx.collections.ObservableList;
 import javafx.fxml.FXML;
 import javafx.scene.control.ListView;
+import javafx.scene.input.ContextMenuEvent;
+import javafx.scene.input.MouseEvent;
 import javafx.stage.Stage;
 import java.util.Arrays;
 import java.util.Optional;
@@ -90,6 +92,19 @@ public class VaultListController implements FxController {
 				}
 			}
 		});
+		vaultList.addEventFilter(MouseEvent.MOUSE_RELEASED, this::deselect);
+		vaultList.addEventFilter(ContextMenuEvent.CONTEXT_MENU_REQUESTED, request -> {
+			if (selectedVault.get() == null) {
+				request.consume();
+			}
+		});
+	}
+
+	private void deselect(MouseEvent released) {
+		if (released.getY() > (vaultList.getItems().size() * vaultList.fixedCellSizeProperty().get())) {
+			vaultList.getSelectionModel().clearSelection();
+			released.consume();
+		}
 	}
 
 	private void selectedVaultDidChange(@SuppressWarnings("unused") ObservableValue<? extends Vault> observableValue, @SuppressWarnings("unused") Vault oldValue, Vault newValue) {

main/ui/src/main/resources/fxml/vault_list.fxml

@@ -15,7 +15,7 @@
 	  fx:controller="org.cryptomator.ui.mainwindow.VaultListController"
 	  minWidth="206">
 	<StackPane VBox.vgrow="ALWAYS">
-		<ListView fx:id="vaultList" editable="true">
+		<ListView fx:id="vaultList" editable="true" fixedCellSize="60">
 			<contextMenu>
 				<ContextMenu>
 					<items>

main/ui/src/main/resources/fxml/vault_list_cell.fxml

@@ -13,6 +13,7 @@
 	  prefWidth="200"
 	  spacing="12"
 	  alignment="CENTER_LEFT">
+	<!-- Remark Check the containing list view for a fixed cell size before editing height properties -->
 	<padding>
 		<Insets topRightBottomLeft="12"/>
 	</padding>