ActionScript 3.0 :: Flash Mysteriously And Partially Disappears?

I� am implementing a charting tool for my project, which is very similar to� Google's finance chart but much more tailored-made to meet different� requirements. The charting interface is made up of the following core components:
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Time� selection panel: to change the time span of the chartMeasurement� points panel: to select different points of measurementChart� area: to display the measurement data of the selected measurement points over the selected time span
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For example,� the Apartment's power administrator can view the total power consumption in Unit 101 of Building A, in the Pacific Apartment's� complex (a made-up name). Similarly, the� administrator can also "stack" up charts of multiple measurement� points, having an all-in-one view like below:
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Only� the chart is implemented in Flash/AS3, the other panels are JSP, JavaScript and Dojo. When an� user clicks on a measurement point to add a chart to the chart area, the following things happen in order� (briefly):
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User clicks on a� link (say,����� Total Amps)Dojo event listener attached to the link picks up the mouse click eventThe Dojo event� listener calls an AS3 method (addChart) through the External Interface to add a chart to the Flash� chart:The Flash chart� picks up the method call, adds a chart to the stage and reposition all charts on the stage. Since the� stage height is fixed at 600 pixels, each chart added will be fitted into the� 600 pixels. Eg, 1 chart on the stage = 600 px/chart, 2 charts = 300� px/chart, 3 charts = 200 px/chart...etc.This is what� the Flash chart looks like, when 3 charts have been added, before display the chart on the actually page� (see below) Once a chart� has been successfully added to the stage, Dojo will stretch the <div> tag that the chart resides so� that each chart still "looks" like 400 pixels tall. For example, 3 charts on� the stage means each chart is 200 pixels tall, but Dojo will stretch the� entire <div> to 1200 pixels, making each chart look like 400 pixelsThe above step� is the same concept as resizing the stage When� an user adds more than 7 charts, the 8th chart will start have� Flash contents disappeared. To be exact, I used firebug to increment the� <div> height, and found that when height exceed 2924 (a magic number) pixels,� Flash contents start to disappear. See below (the red-boxes indicate the� missing contents)The situation gets worse when continue to add charts, eventually half of the� bottom chart will disappear.
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Some pre-work I have done:I have unit tested this component in standalone Flash movie, with 3 LCD monitors� totalling 4000 pixels in height. I produced 10 charts in a single flash movie, and� then resized the window from 600px to 4000px, no charts disappear.� This happens in all of IE7, IE8, FF3+, and Chrome. Although slightly� different manifestation, but they all have contents mysteriously disappeared. This also� happens to GOOGLE's finance chart, when you enlarge the chart's� <div> to over 10000 pxs (yet another magic number) The funny thing is, however, when a graph has been cut in half, the visible half� is still operatable. For example, if the zoom window as been cut in half, I can� still move it, zoom in and zoom out. �