Can't get working Grid

I try to change Table to Grid in my application. Unfortunatelly after 3 days of work I have not been able to see Grid on my page. I change vaadin version from 7.3.8 to 7.7.3 in my ivy file, succesfully compiled widgetset, but instead of grid I see some mess on my screen (see screenshots).
What am I doing wrong???

Problem is in using custom theme. With Valo theme grid is displayed properly.

Yes, looks like a styling issue. Try to use your browser dev tools to identify the styles that break the grid and make them more specific. You may for instance have styles for ‘td’ or ‘table’ somewhere that get applied accidentally.