md复选框悬停突出显示问题

Question

我发现当我将鼠标悬停在md-checkbox上时，当我不想要它时，会在它后面弹出一个浅灰色突出显示。这是我的代码片段。只是想看看是否有人之前遇到过这种情况。

                        <div class="weekday-selection">
                            <div class="weekday-checkbox">
                                <md-checkbox md-no-ink ng-model="weekdays.sunday"
                                ng-change="updateActive(weekdays.sunday)"
                                ng-true-value ="'sunday'"></md-checkbox>
                                <md-checkbox md-no-ink ng-model="weekdays.monday"
                                ng-change="updateActive(weekdays.monday)"
                                ng-true-value ="'monday'"></md-checkbox>
                                <md-checkbox md-no-ink ng-model="weekdays.tuesday"
                                ng-change="updateActive(weekdays.tuesday)"
                                ng-true-value ="'tuesday'"></md-checkbox>
                                <md-checkbox md-no-ink ng-model="weekdays.wednesday"
                                ng-change="updateActive(weekdays.wednesday)"
                                ng-true-value ="'wednesday'"></md-checkbox>
                                <md-checkbox md-no-ink ng-model="weekdays.thursday"
                                ng-change="updateActive(weekdays.thursday)"
                                ng-true-value ="'thursday'"></md-checkbox>
                                <md-checkbox md-no-ink ng-model="weekdays.friday"
                                ng-change="updateActive(weekdays.friday)"
                                ng-true-value ="'friday'"></md-checkbox>
                                <md-checkbox md-no-ink ng-model="weekdays.saturday"
                                ng-change="updateActive(weekdays.saturday)"
                                ng-true-value ="'saturday'"></md-checkbox>
                            </div>
                            <div class="weekday-titles">
                                <span>Sun</span>
                                <span>Mon</span>
                                <span>Tue</span>
                                <span>Wed</span>
                                <span>Thu</span>
                                <span>Fri</span>
                                <span>Sat</span>
                            </div>
                        </div>