I tried to edit multiple tables by ctrl+klick the tabs. 
Writing, copy + paste seems to work fine on all selected tables. 
 
But inserting rows or columns only works on the foreground table.  
 
So I get very strange results.  
  
Example:   
write in table1  
 A1 B1 
 A2 B2 
copy table1 to table2 
select both 
insert column before B with 
 C1 
 C2 
table1 then looks like 
 A1 C1 B1 
 A2 C2 B2 
but table2 looks like 
 A1 C1 
 A2 C2 
and so you lost some information. Assume table1 are data from current year and 
table2 from last year. 
 
Greetings 
Frank Ellenberger