remove redundant property, fix logic error

main/ui/src/main/java/org/cryptomator/ui/health/CheckListController.java

@@ -35,7 +35,6 @@ public class CheckListController implements FxController {
 	private final SimpleObjectProperty<Worker<?>> runningTask;
 	private final Binding<Boolean> running;
 	private final Binding<Boolean> finished;
-	private final BooleanBinding anyCheckSelected;
 	private final BooleanBinding readyToRun;
 
 	/* FXML */
@@ -51,7 +50,6 @@ public class CheckListController implements FxController {
 		this.runningTask = new SimpleObjectProperty<>();
 		this.running = EasyBind.wrapNullable(runningTask).mapObservable(Worker::runningProperty).orElse(false);
 		this.finished = EasyBind.wrapNullable(runningTask).mapObservable(Worker::stateProperty).map(endStates::contains).orElse(false);
-		this.anyCheckSelected = selectedTask.isNotNull();
 		this.readyToRun = runningTask.isNull();
 	}
 
@@ -91,6 +89,7 @@ public class CheckListController implements FxController {
 		try {
 			reportWriter.writeReport(tasks);
 		} catch (IOException e) {
+			//TODO: better error handling
 			LOG.error("Failed to write health check report.", e);
 		}
 	}
@@ -122,10 +121,10 @@ public class CheckListController implements FxController {
 	}
 
 	public boolean isAnyCheckSelected() {
-		return anyCheckSelected.get();
+		return anyCheckSelectedProperty().get();
 	}
 
 	public BooleanBinding anyCheckSelectedProperty() {
-		return anyCheckSelected;
+		return selectedTask.isNotNull();
 	}
 }

main/ui/src/main/resources/fxml/health_check_list.fxml

@@ -23,7 +23,7 @@
 				<Label fx:id="listHeading" text="Health checks"/>
 				<ListView fx:id="checksListView"/>
 				<!-- TODO: clean up button states: -->
-				<Button text="TODO: run selected" onAction="#runSelectedChecks" disable="${controller.anyCheckSelected}" visible="${controller.readyToRun}" managed="${controller.readyToRun}" maxWidth="Infinity"/>
+				<Button text="TODO: run selected" onAction="#runSelectedChecks" disable="${!controller.anyCheckSelected}" visible="${controller.readyToRun}" managed="${controller.readyToRun}" maxWidth="Infinity"/>
 				<Button text="TODO: run all" onAction="#runAllChecks" visible="${controller.readyToRun}" managed="${controller.readyToRun}" maxWidth="Infinity"/>
 				<Button text="%generic.button.cancel" onAction="#cancelCheck" visible="${controller.running}" managed="${controller.running}" maxWidth="Infinity"/>
 			</VBox>