Token browser opens in a lower layer than Site Studio's overlay

Problem/Motivation

Token browser opens in a lower layer than Site Studio's overlay when adding content to a component, making the token browser unusable.

Site Studio's sidebar container has a z-index of 1050 and Gin sets the z-index for the token browser (.ui-dialog.token-tree-dialog) to 505 resulting in the browser opening below the Site Studio overlay and effectively being inaccessible and unusable.

Proposed resolution

Override the z-index for the token browser and set it to something higher.