The attached image is from your service studio. Please publish and see the dropdown in UI. 

Also please include !important in width style if the width of dropdown is too small

SyntaxEditor Code Snippet

.MultiSelectWidth {
width: 175px !important;
}

Hi Shahar

Make sure that the multiple select is encapsulated in a div to match the other filters/inputs.

Then I usually add the following css that overrides the width function in the component and allows to match the other divs in the page.

Hope it helps with your issue.

SyntaxEditor Code Snippet

.ms-parent{
    width: 100%;
}

.ms-drop{
    width: 100% !Important;
}

.ms-choice{
    width: 100% !Important;
}