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Custom Gadget on dashboard | Control chart to be embedded in Custom Gadget.
How Can I add a Custom Gadget on JIRA, the gadget shall be for Control chart, the formulas to be added, inputs of the formula to be decided by user in Dashboard.
You will need to find or write an app that provides the gadget, then install it.
As for the title of your question, which is totally unrelated, see https://community.atlassian.com/t5/Jira-Software-questions/Field-not-showing-in-the-drop-down-menu-of-the-Pie-Chart/qaq-p/762808