Looking at https://help.libreoffice.org/Common/Copying_Attributes_With_the_Clone_Formatting_Tool
I found that Impress tables are not covered.
The only reference to Impress is re "Drawing object is selected".
I believe changing "Writer table or cells are selected" by "Writer or Impress table or cells" would be appropriate (according to my testing with Impress)?
OK -> NEW
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This issue is still valid in LO 7.4. See:
Wee need an entry for "Impress table or cells are selected".
The main problem is that the Clone tool for tables in Impress is too buggy in its current format. I ran a few tests here and nothing worked:
1) It only has any effect inside the same table (does not work across different tables)
2) Even inside the same table results are completely unexpected
Wee need a separate bug report to fix these issues before documenting the Clone tool for Impress tables.