Steps to Reproduce

run the snippet using the atlantic theme:

    <grid width="400px">
        <columns sizable="true">
            <column label="col-1" sort="auto" />
            <column label="col-2" />
            <column label="col-3" sort="auto" />
        </columns>
    </grid>

hover the column separators used to resize the columns.

Current Result

The mouse cursor doesn't indicate resizability for column 1 and 3
Only column 2 switches to a resizing mouse cursor style 'e-resize'

Expected Result

Always display the resizing mouse cursor.
(preferably: ew-resize as used in other themes)

Debug Information

the .z-column-sort .z-column-content styles have a higher specificity

Workaround

add a custom style

    <style>
        .z-column-sizing,
        .z-column-sort.z-column-sizing .z-column-content {
            cursor: ew-resize;
        }
    </style>