Active X Textbox Content to Userform Textbox

[swaggerbox]

I have a workbook with multiple active x textboxes. I want to have expanded view for each textbox and would prefer a userform textbox. Each time the user double clicks on the active x textbox, the userform is displayed filled with the contents of the active x textbox. In the userform, the user can edit the content and save the content back to the active textbox as well. I don't want to create multiple userforms for each active textbox and would prefer only one. My problem is how to code macro telling which active textbox to import. I have attached a sample workbook to illustrate this problem.