Can't add row or columns!

It's Chrome 57.0.2987.133

When I click on the + sign, nothing happens.  I have many plugins, and maybe one interferes, but I use them, so I don't want to put them off. 

I used Windows Explorer instead and it worked just fine. 

Thanks

I'm having the same issue (unable or at least very sporadically able to add rows/columns to a table). I'm facing this on macOS Sierra, across the latest versions of Chrome, Firefox, and Safari. Resetting the chrome beta flags as suggested by others does nothing. Dropbox support was zero help when I got in touch.

I have found a workaround however that could be helpful to others:

1. copy your table from your paper doc and paste into a simple text editor, and you'll get the underlying github flavored markdown table structure, e.g.:

| Col A | Col B | Col C |
| ----- | ----- | ----- |
| one   | two   | three |
|       |       |       |
|       |       |       |

2. Within your text editor, add whatever rows/columns you want.

3. Copy and paste that raw text back into your Paper doc, replacing your broken table.

It's not the most wonderful editing experience, in what in pretty much all other respects is my current favorite text editor, but it gets the job done