resizeCanvas() does not take into account the preHeader height

I have created a grid with the wollowing options:

                        autoEdit: false,
                        editorCellNavOnLRKeys: true,
                        enableAutoResize: true,
                        enableCellNavigation: true,
                        enableColumnReorder: false,
                        enableGrouping: false,
                        frozenColumn: 0,
                        createPreHeaderPanel: true,
                        editable: true,
                        explicitInitialization: true,
                        preHeaderPanelHeight: 25,
                        showPreHeaderPanel: true,
                        autoResize: {
                        containerId: $('#MyGrid')

On calling resizeCanavas(), e.g.

                         $(window).resize(function () {
                             grid.resizeCanvas();
                         });

the height of the grid is reduced by 25px.

[xavier-90]

I have done further tests and found that I was actually “barking at the wrong tree”. The issue is with the resizer: If setting the resizer bottom padding to 0 then the grid is rendered with a bottom padding of 20px (the default). I have logged this as #504

[xavier-90]

I had to make a minor mod for it to work correctly in my scenario (inside a flex grow column height 100%): The viewportTopH does no need to include the preHeaderHeight.

Also made a change to take into account the showPreHeaderPanel value.

function resizeCanvas() {
      if (!initialized) { return; }
      paneTopH = 0;
      paneBottomH = 0;
      viewportTopH = 0;
      viewportBottomH = 0;
+      var preHeaderHeight = (options.createPreHeaderPanel && options.showPreHeaderPanel) ? (options.preHeaderPanelHeight || 0) : 0;

  //-- ... code removed for brevity --//

      // The top pane includes the top panel and the header row
+      paneTopH += topPanelH + preHeaderHeight + headerRowH + footerRowH;

      if (hasFrozenColumns() && options.autoHeight) {
        paneTopH += scrollbarDimensions.height;
      }

      // The top viewport does not contain the top panel or header row
      viewportTopH = paneTopH - topPanelH - headerRowH - footerRowH;