Grid calculates row height only on Hover

[ceisserer]

When using a Grid with autoHeight enabled, lines > default height are only sized appropriatly when the mouse hovers the row, because this cases _onRowRendered to be invoked.
This is a regression compared to RAP 3.11, however I am not sure exactly which commit did introduce it.

The issue does not reproduce when creating the grid directly in createContents(), as this causes _onRowRendered to be invoked twice, where the second calls performs the correct computation. However when creating the Grid during an event, _onRowRendered is only called once, in which case the calls to computeAutoHeight() seem return some dummy value (10).

Reproducer:

public class BasicEntryPoint extends AbstractEntryPoint {

  protected void createContents(Composite parent) {
	  parent.setLayout(null);
	  
	  Button createBtn = new Button(parent, SWT.PUSH);
	  createBtn.setText("Create grid");
	  createBtn.setBounds(100, 50, 200, 20);
	  createBtn.addListener(SWT.Selection, e -> createGrid(parent));
  }
  
  protected void createGrid(Composite parent) {
	    Grid grid = new Grid(parent, SWT.BORDER | SWT.V_SCROLL | SWT.H_SCROLL);
	    grid.setData(RWT.MARKUP_ENABLED, true);
	    grid.setAutoHeight(true);
	    grid.setBounds(100, 100, 500, 500);
	    
	    GridColumn col = new GridColumn(grid, SWT.NONE);
	    col.setText("Multi Line Column");
	    col.setWidth(500);
	    
	    GridItem item = new GridItem(grid,SWT.NONE);
	    item.setText("Multi <br/> Line");
  }
}