increase fabric canvas height

templates/impress.cs/js/slide-drawing.js

@@ -53,7 +53,7 @@ function slide_drawing_init(paneId) {
             </div>
         </div>
         <div id="fabric-canvas-div">
-            <canvas id="fabric-canvas" width="2000" height="800"></canvas>
+            <canvas id="fabric-canvas" width="2000" height="2000"></canvas>
         </div>
     `;