How do I delete a table column?

In the Table Widget I clicked the tiny marker next to a column and it added another column. I thought if I clicked the marker to the left of the column it would delete it, but it added another column. How do I delete a column? This is in Captivate 2017 with Windows 10. I added the table by clicking Insert > Widget > Table.

Use a shape as a button on a layer

How can I create buttons on the layer?