Fix exception when no columns are shown (#8733)

* Fix exception when no columns are shown or all columns are frozen

Fixes #8329

1 files changed, 17 insertions, 9 deletions

diff --git a/client/src/main/java/com/vaadin/client/widgets/Escalator.java b/client/src/main/java/com/vaadin/client/widgets/Escalator.java
index 239ed9b90b..7eb99badf7 100644
--- a/client/src/main/java/com/vaadin/client/widgets/Escalator.java
+++ b/client/src/main/java/com/vaadin/client/widgets/Escalator.java
@@ -701,13 +701,13 @@ public class Escalator extends Widget
         /*-{
             var vScroll = esc.@com.vaadin.client.widgets.Escalator::verticalScrollbar;
             var vScrollElem = vScroll.@com.vaadin.client.widget.escalator.ScrollbarBundle::getElement()();
-
+        
             var hScroll = esc.@com.vaadin.client.widgets.Escalator::horizontalScrollbar;
             var hScrollElem = hScroll.@com.vaadin.client.widget.escalator.ScrollbarBundle::getElement()();
-
+        
             return $entry(function(e) {
                 var target = e.target;
-
+        
                 // in case the scroll event was native (i.e. scrollbars were dragged, or
                 // the scrollTop/Left was manually modified), the bundles have old cache
                 // values. We need to make sure that the caches are kept up to date.
@@ -728,29 +728,29 @@ public class Escalator extends Widget
             return $entry(function(e) {
                 var deltaX = e.deltaX ? e.deltaX : -0.5*e.wheelDeltaX;
                 var deltaY = e.deltaY ? e.deltaY : -0.5*e.wheelDeltaY;
-
+        
                 // Delta mode 0 is in pixels; we don't need to do anything...
-
+        
                 // A delta mode of 1 means we're scrolling by lines instead of pixels
                 // We need to scale the number of lines by the default line height
                 if(e.deltaMode === 1) {
                     var brc = esc.@com.vaadin.client.widgets.Escalator::body;
                     deltaY *= brc.@com.vaadin.client.widgets.Escalator.AbstractRowContainer::getDefaultRowHeight()();
                 }
-
+        
                 // Other delta modes aren't supported
                 if((e.deltaMode !== undefined) && (e.deltaMode >= 2 || e.deltaMode < 0)) {
                     var msg = "Unsupported wheel delta mode \"" + e.deltaMode + "\"";
-
+        
                     // Print warning message
                     esc.@com.vaadin.client.widgets.Escalator::logWarning(*)(msg);
                 }
-
+        
                 // IE8 has only delta y
                 if (isNaN(deltaY)) {
                     deltaY = -0.5*e.wheelDelta;
                 }
-
+        
                 @com.vaadin.client.widgets.Escalator.JsniUtil::moveScrollFromEvent(*)(esc, deltaX, deltaY, e);
             });
         }-*/;
@@ -4097,6 +4097,10 @@ public class Escalator extends Widget
          */
         @Override
         public void removeColumns(final int index, final int numberOfColumns) {
+            if (numberOfColumns == 0) {
+                return;
+            }
+
             // Validate
             assertArgumentsAreValidAndWithinRange(index, numberOfColumns);
 
@@ -4225,6 +4229,10 @@ public class Escalator extends Widget
          */
         @Override
         public void insertColumns(final int index, final int numberOfColumns) {
+            if (numberOfColumns == 0) {
+                return;
+            }
+
             // Validate
             if (index < 0 || index > getColumnCount()) {
                 throw new IndexOutOfBoundsException("The given index(" + index