Please, give more info: which product (Acrobat/Reader), which version (including minor), which platform (Win/Mac), which OS/version?
For Reader 11.0.9 I presume you are doing the following. In the Fill&Sign panel on the right you click on "Place Signature". You used to click on some place in the document and got your signature right there, right? Now you are getting the "Drag New Signature Rectangle" dialog, right? What I think has happened was that you somehow changed the type of the "saved signature" to "Use Certificates". To the right of the "Place Signature" button there is a small triangle. Click on it and then select "Change Saved Signature". You will be presented with a dialog which allows you to select the signature type you want to use for this signature and in the future. Select the signature type you used before and you'll get the expected behavior.