Indicates which mouse button or buttons were pressed down (held down) when a given event occurred, as shown in the following table. Return values can occur together; for example, a return value of 3 indicates that both the left and right buttons were pressed down when the event occurred. Read-only Long.
| Value | Meaning |
|---|---|
| 0 | No mouse buttons were pressed down. |
| 1 | The left mouse button was pressed down. |
| 2 | The right mouse button was pressed down. |
| 4 | The center mouse button was pressed down. |