Problem with grid show() hide() IE

[gaseguraj]

Hello everybody, yeah again IE, My problem is: I have a tabpanel with 2 tabs.
In my first tab i have a grid (Master) and the second I have two grid A and B.
If in the first grid Master I select some row it showme the A grid and the B grid hide, and if I selected other one row the A grid hide and the B grid Show.

On firefox works fine, but with IE the second grid don't show and throws an error "Invalid Argument": I saw the debugcode and the line is:

this.activeHdBtn.dom.style.height = (hd.firstChild.offsetHeight-1)+'px';

The picture is in the atachment.

The Code hide show

if(....)
  Apps.gestionar.storeActuacionAsesoria.load();
  Apps.gestionar.gridActuacionAsesoria.show();
else...
 Apps.gestionar.storeActuacionAsesoria.show();
  Apps.gestionar.gridActuacionAsesoria.hide();