# The Mouse

The mouse is used to set point, mark and the block.

- Button 1 in the cell area moves point
- Button 1 on vertical grid line adjusts column width
- Button 1 on horizontal grid line adjusts row height
- Button 1 on grid line crossing does autofill
- Button 2 in the grid inserts the current selection
- Button 3 (or Shift - Button 1) in the grid extends the selection
- Button 1 in column header sets block to the clicked column
- Button 1 between column headers adjusts column width
- Double-click button 1 in column header automatically adjusts column width
- Button 3 in column header extends the selection
- Button 1 in row header sets block to the clicked row
- Double-click button 1 in row header automatically adjusts row height
- Button 3 in row header extends the selection

Moving the mouse in the grid with button 1 pressed defines the selection.

Mice with fewer than 3 buttons can be used by changing the app-defaults.

This behaviour is consistent with most other X applications.

The selection can be cleared directly by calling the function (unset-block) (Block - Unset Block on the menu) or indirectly by selecting something else in another part of the grid, in another instance of Siag or in another X application.

### Autofill

Autofilling works by placing the pointer over a grid line crossing, pressing down, dragging to the lower right corner of the area you want to fill and releasing. The neat thing about this is that you can automatically get series of values by following this example:

1. Enter 2 into cell A1
2. Enter 5 into cell B1
3. Position the pointer over the lower right corner of A1, so that the pointer changes shape
4. Click down and hold
5. Move the pointer to F1
6. Release

The area is filled with 8 in C1, 11 in D1, 14 in E1 and 17 in F1.