it has to be shown as <--> like this
This is by design. In the Scheduler, the left edge uses "w-resize" cursor and the right edge uses "e-resize" cursor.
If you don't like the appearance you can replace the built-in resize margins by active areas and override the default cursor using CSS.
See this tutorial for an example: https://code.daypilot.org/84763/html5-scheduler-for-touch-devices-ipad-android-php-javascript