Someone may already have had this issue and reported it previously at https://phabricator.wikimedia.org/T108712 unrelated

I can only edit the headings of the table but not the other cells.

Steps to reproduce:

1. Go to https://en.wikipedia.org/wiki/The_Real_Housewives_of_Orange_County_(season_12) with Firefox Version 56.0.2 (64- bit) or Chrome Version 63.0.3239.84 (Official Build) (64-bit) (Chrome up to date as of the writing of this);
2. Make sure you are logged in;
3. Click "edit";
4. Visual Editor should appear;
5. Go to "Episodes" table;
6. Double-click on empty space on the cell named "Title";
7. A text cursor should appear;
8. Click on the "10" citation;
9. A dialog box with information and an edit button should appear;
10. Double-click "Vicki" in the first cell under the table heading "No. in series";
11. Selected text just flashes instantaneously, you can't select text and the text cursor doesn't appear, you can't edit the cell;
12. Go to the cell named "1.68" under the table heading named "U.S. viewers (million)";
13. Double-click on empty space in the cell;
14. Nothing happens, except a flicker of a line, text cursor doesn't appear, you can't edit the cell;
15. Click on the "11" citation;
16. The start of the article in visual editor appears, or alternatively, the "11" citation under the section "References" appear -no longer in visual editor; edition of the citation template is not possible.

Actual Results:
Can't edit the cells nor the citation templates except the cells of the table headings and their citation templates.

Expected Results:
Should be able to edit all the cells of the table and their citation templates.

Other information that might be useful:

• Using a laptop with Windows 10 Single Language (Spanish version), 64 bits.
• This bug may be only in the article "The Real Housewives of Orange County (season 12)"; I tried another article with a table (List of countries by firearm-related death rate https://en.wikipedia.org/wiki/List_of_countries_by_firearm- related_death_rate) but there was no bug in the table there, so I was able to edit the cells there.