Filters selection type:dropdown issues

I've created a view gmap page with taxonomy terms. I activated Content: Has taxonomy term from Filter criteria, marked the right taxonomy terms and exposed with dropdown. On the page there are exposed filter and the content (in this case gmap). From the firebug menu I can see the classes for view-filters and view-content. When I click on the filter, the dropdown appears with all the categories, but when I hover one of them they аre disappearing immediately, so I cannot select any category filter. I've noticed when I click on exposed filter I can select the options only with the keyboard, but not with the mouse.
I've seen this problem one month before with other project and I've fixed it with creating a separate block, not page, but in this case View page is the only right option.