<button type="button" ng-if="$ctrl.visible"
    ng-class="{ 'btn-info': $root.showprojectexplorer, 'btn-unselected': !$root.showprojectexplorer }" 
    uib-tooltip="{{'projectexplorer_tooltip'+$root.os | translate}}"
    class="btn" ng-click="$ctrl.toggleProjectExplorer()">
    {{'detailfooterleftbuttonbar.projectexplorer.button' | translate}}
</button>