great, well thanks for finally responding to bcm1212's original post by saying clearly that "It is not possible to disable it." and with that, thank you for answering my question.
if i can provide some feedback to the Adobe company on this feature in Acrobat, i'd like to say :
- the popup menu is annoying (to some users including myself) because it gets in the way and most often obscures the document i am trying to work on. i don't like things getting in the way, and even though it is intended to be a helpful feature, it is often not helpful.
- i think this popup menu may be more helpful if it can be toggled to enable/disable and if it had the option to show up either right next to what you select (because i'm sure some people may appreciate how it is currently) or to show up maybe on a toolbar or something where it cannot obscure the document that i am trying to work on.
Hi All,
We have released an update today for Adobe Acrobat 2015, Acrobat 2017 and Acrobat DC in which you can hide the toolbar using a newly added preference. By default, the toolbar is enabled. Check the screenshot below:

This update will be automatically pushed to all existing installations of Acrobat and Reader. If you want, you may also manually trigger the update early by opening the application and going to Help > Check for Updates.
You may refer to the following link to check the latest versions available. Release Notes | Adobe Acrobat, Reader
For more details on the new update, please refer to the following help document What's new in Adobe Acrobat DC
Let us know if you have any questions.
Regards,
Meenakshi