My Jotform is not allowing me to add Text (from the list of 'basic fields')

My Jotform is not allowing me to add Text (from the list of 'basic fields'), it is loading and not showing the usual box.  

I have checked your form and I can see you've added some text fields, here are some screenshots about what I can see on my end: 

Please do note that when you add a Text field to your form and you do not change it, the field will not be displayed when the form is previewed. 

You need to add your custom text by clicking on the Edit HTML button: 

Then once you've finished customizing your text, click on the complete button to save changes: 

Please if you still have problems with adding or editing the text field, do let us know, we will be glad to help. 

When I 'double click' a small box appears and a never ending 'please wait.
No other details....
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I have cloned your JotForm to my account and see that the Text field is editable at my end. Please see the screencast below:

Could you try logging to a private/incognito window or a separate browser to see if the text field can be edited? You may also try force reloading the form builder by pressing Ctrl+F5 after opening the form in edit mode. Let us know how it goes.

Let us know how it goes. We will be happy to assist you further.