Show/hide buttons- Slide-In Table of Contents: Close Button Issue

Hi experts,

I have done a product that has a slide-in table of contents on every page. I have done a button to open the box of contents and a button to close it. They are aligned on the top of each other.  Have Published the product Online. Works fine!

But. When you click the open button, and the close button shows, you HAVE TO MOVE your cursor away from the close button and to come back on it to make the table of contents to vanish. Otherwise the  slide-in box just makes a small move and stays.

I would like to have these buttons aligned on each other so can we fix this somehow not needing to "separate" them or the customer to understand to move the cursor and come back? Normally one would do it, but in case the cursor stays on the button, one cannot close the box. Hope you understand my problem. I do not want to confuse the reader in any situation. 

So happy if you could take your time to think about this, please.

Anna-Maija

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