| Rectangle Selection |  | Allows selection in rectangle mode on mouse drag. | 
| Lasso Selection |  | Allows selection in lasso mode on mouse drag. | 
| Structure Selection |  | Allows selection in structure selection mode on mouse drag. With this selection mode, only whole fragments can be selected. | 
| Erase |  | Removes all structures upon selection. | 
| Undo |  | Reverses the last command or the last entry you typed. | 
| Redo |  | Reverses the action of the last undo command. | 
| Cut |  | Removes and copies the selection to the clipboard. | 
| Copy |  | Copies the selection to the clipboard. | 
| Paste |  | Inserts the contents of the clipboard at the location of the cursor, without replacing selection. | 
| Check Structure |  | Checks and corrects chemical structures. See Structure Checker User's Guide for more information. | 
| Zoom In |  | Increases the magnification of the canvas. | 
| Zoom Out |  | Decreases the magnification of the canvas. | 
| Zoom Tool |  | Changes the magnification of the canvas to a specific value.  It can also do autoscale using the following named values: All, Selection, Scaffold (only when an R-group is defined on the canvas), and R-group (only when an R-group is defined on the canvas) | 
| Help Contents |  | Shows MarvinSketch User's Guide. |