Fixes undefined reference to 's'

components/TitleBar.qml

@@ -26,7 +26,7 @@
 // STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF
 // THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
-import QtQuick 2.2
+import QtQuick 2.5
 import QtQuick.Window 2.0
 import QtQuick.Layouts 1.1
 
@@ -64,7 +64,7 @@ Rectangle {
     Item {
         // Background gradient
         width: parent.width
-        height: s
+        height: parent.height
         z: parent.z + 1
 
         Image {