Replied 8 September 2017, 2:22 pm EST
While using FormulaTextBox along with the Spread we are able to get the Spread's CustomNames in the FormuaTexBox automatically. Please have a look at the attached sample and let us know your further observations on the same.
I have a ttached a screenshot of the same as well, wherin the three CustomNames i have made( test, test1, test2) are visible in FormulaTextBox.
And for the second question, we are able to get the formula textbox in Spread's Cell but the dropdown facility is not available. However, we have added it as an enhacement request for future release,and the request Id is #999166658.