In Editing Panel, you may find the tools of Crop and Auto Crop.
To crop a image,
In view | editing mode, click button Crop and a dialog pop up.
You may outline the area (selection) by holding down the left mouse button. Then click button Crop it or click Done to Crop the image.
To Auto Crop a image,
If you want to crop image to some often-used proportions like 4R, 5R etc, click button Auto Crop and from the menu list, click the size or proportion you want to apply it to the image.
To save your editing, please click button Save in the toolbar on the top.
To undo or redo your editing, please click the tab Editing History on the bottom of Editing Panel, all your editing history is listed and click one of them to roll back.