Weird CSS behavior

Hi, I have quite strange problem with the slickgrid display. I use 2 themes on the site - default and administrative and use slickgrid with the administrative one. When open the slickgrid page it implements the administrative theme css. However when I try to edit a cell and дзех a modal window all of a sudden the page implements the css form the default theme.
Another problem - I have beauty tips activated on the slickgrid cells and they seem to be non-active until I open a modal window. After that they are active until I refresh the page. And again...
Does anyone have an idea where to look for solutions?