Any modification that you make to a structure applies only to the selected atoms or bonds In addition, when a (Sub)Structure search is initiated, the program automatically uses the selected (sub)structure in Structure. Before you select one or more atoms you should restore the default state of the editor. To select a group of atoms that are next to each other:

• Hold down the mouse button and drag a rectangle around the atoms you want to select.

The usual Windows convention for selecting multiple items applies. To select atoms at different locations, you should use the keyboard SHIFT key. You can select a group of atoms that are not adjacent in one of two ways:

• Click the atoms you want to select, while holding down the SHIFT key.
• Or hold down the mouse button and drag a rectangle around the atoms you want to select, while holding down the SHIFT key.

If you want to select all of the atoms and bonds in the structure:

• Click the Select All button  in the Structure Editor window or choose the Structure | Select All menu item.
• Or double click anywhere in the draw area within Structure Editor, except on atoms and bonds.

Structure Editor offers two selection modes: Rectangle Selection and Lasso Selection. To choose the selection mode that fits your needs:

• Click with the right mouse button on the Default Mode  button and choose the appropriate selection mode from the popup menu.
• Or click with the right mouse button anywhere in the draw area within Structure Editor, and click the Rectangle or Lasso Selection menu item on the pop-up menu that will appear in the draw area.