Improve layout of pad selection in trigger settings

PlayWallCore/src/main/java/de/tobias/playpad/view/main/ProjectPreviewView.java

@@ -6,6 +6,9 @@ import de.tobias.playpad.project.Project;
 import de.tobias.playpad.project.page.Page;
 import javafx.collections.FXCollections;
 import javafx.collections.ObservableList;
+import javafx.geometry.Insets;
+import javafx.geometry.Pos;
+import javafx.scene.Node;
 import javafx.scene.control.Pagination;
 import javafx.scene.control.ToggleButton;
 import javafx.scene.control.Tooltip;
@@ -24,22 +27,27 @@ public class ProjectPreviewView extends Pagination {
 		this.selected = FXCollections.observableArrayList(preSelect);
 
 		setCurrentPageIndex(initialPage);
-		setPageFactory(index -> {
+		setPageFactory(this::getPageNode);
+	}
+
+	private Node getPageNode(int index) {
 		GridPane gridPane = new GridPane();
 		gridPane.setHgap(7);
 		gridPane.setVgap(7);
+		gridPane.setAlignment(Pos.CENTER);
+
+		gridPane.setPadding(new Insets(0, 0, 7, 0));
 
 		final Page page = project.getPage(index);
 		for (int x = 0; x < project.getSettings().getColumns(); x++) {
 			for (int y = 0; y < project.getSettings().getRows(); y++) {
 				final Pad pad = page.getPad(x, y);
-					ToggleButton toggleButton = getToggleButton(preSelect, pad);
+				ToggleButton toggleButton = getToggleButton(selected, pad);
 
 				gridPane.add(toggleButton, x, y);
 			}
 		}
 		return gridPane;
-		});
 	}
 
 	private ToggleButton getToggleButton(List<Pad> preSelect, Pad pad) {