angularjs - angular-ui/ui-select inside a custom directive -

i using angular-ui/ui-select inside custom angular directive, when first load page, or full browser refresh, dropdown menu not appear when click dropdown arrow, however, if navigate state (yes i'm using ui-router) go state has dropdown, dropdown works fine. here couple of observations:

• i tried both use prototypal inheritance , isolated scope directive, in both cases, erroneous behaviour present.
• i moved dropdown outside directive , works fine.

does know doing wrong?

thanks