By default, the AllowZoomOnFly property is 0, exNoZoomOnFly. In other words, the Zoom-OnFly view is never displayed by default. The Zoom-OnFly view was provided to let you magnify a portion of the chart without affecting the chart's scale. The Zoom-OnFly view displays the item and its neighbors from the cursor, and additional information about the bar from the cursor. The Zoom-OnFly scale is indicating by the chart's ResizeUnitScale property. If the chart's ResizeUnitScale property is not specified, the Zoom-OnFly uses the chart's UnitScale property to indicate the inside scale. The ZoomOnFlyCaption property indicates the HTML caption to be displayed as addition information for the bar/task from the cursor. The BackColorZoomOnFly property indicates the Zoom-OnFly's background color. The Zoom-OnFly view is shown on the chart once the user presses the CTRL +/ SHIFT keys and the the chart is active/focused. The Label property indicates the label to be shown in the Zoom-OnFly view. Set the ZoomOnFlyCaption property on empty, to display no addition information about the bar from the cursor. Use the SelectOnClick property to prevent selecting a row / item when clicking the chart portion of the control.

The following screen shot shows the Zoom-OnFly view, after the user presses the CTRL + SHIFT keys combination ( You can notice that the inside scale displays hours, while the master chart displays days ):

The following screen shot shows the chart before pressing the CTRL + SHIFT keys ( before showing the Zoom-OnFly view ):

This feature could be very useful:

• if you require to display additional information about bars.
• if you need to align different bars based on other bars
• refines moving or sizing the bars based on another scale. For instance, if the main chart displays days, you can have the Zoom-OnFly view displaying hours, so resizing is very easily to be precise. 

Click here to watch a movie on how you can resize or move bars if precision is required.

Here's a few samples on how to use the AllowZoomOnFly property:

• = exZoomOnFly ( 24 ), the Zoom-OnFly view is shown if the cursor hovers any part of the control's chart, and presses the CTRL + SHIFT combination. The view shows the item from the cursor including the bar from the cursor.
• = exZoomOnFly + exZoomOnFlyBarsOnly (56), the Zoom-OnFly view is shown if the cursor hovers any BAR of the control's chart, and presses the CTRL + SHIFT combination. The view shows the item from the cursor including the bar from the cursor, and shows nothing if there is no bar at the cursor position.
• = exZoomOnFlyShift + exZoomOnFly (25), same as the exZoomOnFly excepts that the view can be shown if the SHIFT is pressed, not requiring pressing the CTRL + SHIFT
• = exZoomOnFlyCtrl + exZoomOnFly (26), same as the exZoomOnFly excepts that the view can be shown if the CTRL is pressed, not requiring pressing the CTRL + SHIFT
• = exZoomOnFly + exZoomOnFlyIncludeNeighborItems (280), same as the exZoomOnFly, excepts that the view displays the previously visible item, and the next visible item, if they exists. Use this option to display more than one item in the view for better alignment of the bars based on their neighbors.
• = exZoomOnFly + exZoomOnFlyIncludeSelectedItems (792), same as exZoomOnFly + exZoomOnFlyIncludeNeighborItems, excepts that the view displays the previously selected item, and next selected item. Use this option to include the next and previously selected items for a better comparing between selection and the item from the cursor. 
• = exZoomOnFlyShift + exZoomOnFly + exZoomOnFlyIncludeSelectedItems (793), same as exZoomOnFly + exZoomOnFlyIncludeSelectedItems, excepts that the view can be shown if the SHIFT is pressed, not requiring pressing the CTRL + SHIFT
• = exAllowInfoOnFly (16), the Zoom-OnFly view is shown if the cursor hovers any part of the control's chart, and presses the CTRL + SHIFT combination. The view shows the item from the cursor including the bar from the cursor. The view is closed as soon as the cursor hovers another part, or if the user presses the mouse. 
• = exZoomOnFlyCtrl + exAllowInfoOnFly (18), same as exAllowInfoOnFly, excepts that the view can be shown if the SHIFT is pressed, not requiring pressing the CTRL + SHIFT
• = exAllowRefineOnFly (8), the Zoom-OnFly view is shown only if the user clicks while pressing the CTRL + SHIFT combination.