| Part | Description | |
| object | Required. A valid object. | |
| index | Required. The index of the page or tab in a MultiPage or TabStrip with the specified event. | |
| Button | Required. An integer value that identifies which mouse button caused the event. | |
| Shift | Required. The state of SHIFT, CTRL, and ALT. | |
| X, Y | Required. The horizontal or vertical position, in points, from the left or top edge of the form, Frame, or Page. | |
| Constant | Value | Description | |
| fmButtonLeft | 1 | The left button was pressed. | |
| fmButtonRight | 2 | The right button was pressed. | |
| fmButtonMiddle | 4 | The middle button was pressed. | |
| Value | Description | |
| 1 | SHIFT was pressed. | |
| 2 | CTRL was pressed. | |
| 3 | SHIFT and CTRL were pressed. | |
| 4 | ALT was pressed. | |
| 5 | ALT and SHIFT were pressed. | |
| 6 | ALT and CTRL were pressed. | |
| 7 | ALT, SHIFT, and CTRL were pressed. | |
| Constant | Value | Description | |
| fmShiftMask | 1 | Mask to detect SHIFT. | |
| fmCtrlMask | 2 | Mask to detect CTRL. | |
| fmAltMask | 4 | Mask to detect ALT. | |