I have situation where there are 2 grids say grid1(default),grid2 occupying the same space. At any given time depending on choice made using a radio button, one of the grids is shown .
grid1 is shown by default - this has a paging tool bar.
grid2 doesnt have a paging tool bar and hidden by default.
The paging tool bar doesnt appear in the following scenario :
1)grid1 is displayed - paging tool bar is completely visible
2)User chooses to display grid2
3)Both the stores of grid1 and grid2 are reloaded (some other parameter changes)
4)user switches to view grid1 - paging tool bar is not displayed..
If grid1 is visible and the stores are reloaded- paging toolbar is displayed but slightly hidden.
It would be hard to say without seeing any code, but I would suggest using a card layout and place a grid on each panel .. then simply toggle the panel to be displayed instead of playing games with trying to hide/show grids.
You can test this on a tabPanel and move to a card layout when done.