I not sure if the question has been asked or not. I tried to find something similar without success.

I have this small code:

Manipulate[Plot[Sin[a x], {x, 0, 2}], {a, 1, 10}]

The output is ok. when I changed a using the Manipulate controller bar, the output is ok too. But when I used the keyboard to enter value of a and then Enter, I get a duplicate output:

enter image description here

Did I do something wrong to get this output?

Thank you

  • 1
    $\begingroup$ I can reproduce that only for Shift+Enter event or numeric keyboard Enter. It always has been a little bit annoying. $\endgroup$
    – Kuba
    Jan 7, 2015 at 19:25
  • 2
    $\begingroup$ Very annoying.. $\endgroup$ Jan 7, 2015 at 19:28
  • 2
    $\begingroup$ Shift+Enter means evaluate the current cell (if it is evaluatable). When you evaluate a Manipulate output, it evaluates to another (instance of a) Manipulate, as well as converting the output cell to an input cell as shown by the In/Out tags in your screen shot. However annoying it is, the behavior is quite consistent with the documented behavior sifht+enter, which must be familiar to any somewhat experienced user. $\endgroup$
    – Michael E2
    Jan 7, 2015 at 21:13
  • 1
    $\begingroup$ Using Enter (Return keyboard button without shift) solves the issue. $\endgroup$ Jan 7, 2015 at 22:05
  • $\begingroup$ I use Tab myself, but it changes focus and selects the InputField text. $\endgroup$
    – Michael E2
    Jan 7, 2015 at 22:10

2 Answers 2


Your code defines the Control to be a Slider by default. Typing into a different device, the InputField, yields a separate computation and separate output cell.

If you'd like to change the Control for input to be an InputField so you can type different values of a without producing different output cells, try this:

Manipulate[Plot[Sin[a x], {x, 0, 2}], {{a, 5}, InputField}]

A workaround I use is to put a semicolon at the end of the graph in the Manipulate Cell, this prevents printing more copies of the graph each time data is entered in the InputField.


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