On dataProvider change labels changes chart doesn't

Question

I have a flex application, which consists of several tabs. One tab contains a columnchart and a datagrid, which contains collection of results (after selecting another datagrid result, another line in the chart shows up). This stops, however, after I go to another tab and come back. At this point, after datagrid line is selected, chart's dataProvider changes, which causes labels to change, but chart remains the same.

Tab navigation is implemented through states, like this:

<s:states>
 <s:State name="tabWithChart"/>
 <s:State name="anotherTab"/>
 <s:State name="yetAnotherTab"/>
</s:states>

...................

<s:Group>
 <chartTab:ChartTab includeIn = "tabWithChart"/>
 <tab1:Tab1 includeIn = "anotherTab"/>
 <tab2:Tab2 includeIn = "yetAnotherTab"/>
</s:Group>

Clicking navigation button causes state to change. What may be causing the problem?