I have an APEX tabular form, all columns of which are standard report columns. Is it possible to display a tooltip on mouse over of a particular cell of the report?
In the report column attributes look for the region named Column Formatting. Inside this section is a text box for an "HTML Expression". Here you can add html to the report column contents e.g., <span title="My tooltip text">#COLUMN_NAME#</span>
The tooltip text could be from another column, you would just replace the contents of the title attribute with the column name surrounded by hashes.