Your custom mass actions dropdown is very similar to the standard one (it is located at the left side above the grid on your screenshot).
As an example, see how is the standard mass actions dropdown implemented for the backend CMS pages grid.
Your custom mass actions dropdown is very similar to the standard one (it is located at the left side above the grid on your screenshot).
As an example, see how is the standard mass actions dropdown implemented for the backend CMS pages grid.