enable elasticX only for render, if mouseZoomable or focusChart

elasticX can reasonably be interpreteted as "just calculate the domain for me, unless it's forced by something else"
so ignore it during redraw if this is a focus chart or mouseZoomable is active
fixes #1623, #987

src/coordinate-grid-mixin.js

@@ -479,7 +479,7 @@ dc.coordinateGridMixin = function (_chart) {
 
     function prepareXAxis (g, render) {
         if (!_chart.isOrdinal()) {
-            if (_chart.elasticX()) {
+            if (_chart.elasticX() && (render || (!_chart.mouseZoomable() && !_rangeChart))) {
                 _x.domain([_chart.xAxisMin(), _chart.xAxisMax()]);
             }
         } else { // _chart.isOrdinal()
@@ -500,6 +500,9 @@ dc.coordinateGridMixin = function (_chart) {
                 _x.domain(_chart._ordinalXDomain());
             }
         }
+        if(render && _chart.elasticX()) {
+            _xOriginalDomain = _chart.x().domain();
+        }
 
         // has the domain changed?
         var xdom = _x.domain();
@@ -1236,7 +1239,7 @@ dc.coordinateGridMixin = function (_chart) {
 
         _chart.plotData();
 
-        if (_chart.elasticX() || _resizing || render) {
+        if (_chart.elasticX() && (!_chart.mouseZoomable() && !_rangeChart) || _resizing || render) {
             _chart.renderXAxis(_chart.g());
         }