To reproduce:
Create version 1.0
Create version 1.1 which is a child version of 1.0
create a context different from the default
create an agile gadget for the test project

Now, in the agile gadget, select the velocity tab. All appears normal. ( Step1.png )

Go to the chart board and switch the context. Values appear normal for the context ( Step2.png)

Update the chart in the Agile gadget. Now the values display for selected context in the chart board even though the Default context remains selected in the gadget. ( Step3.png )

No matter what context one selects for the Agile gadget it will not update until you switch the corresponding chart in the chart board.

This affects JIRA 4.1.2 with GreenHopper 5.1