In Toad one can easily execute current line without highlighting it. Let say, you have a worksheet like this:
select * from item -- cursor here
select * from p
I also ran into a similar situation where Ctrl+Enter shortcut stopped working for executing any statement and had to highlight the entire statement for executing it.
How it worked: (i) By removing/commenting out all the comments in the worksheet i.e. just have only the Sql statements in the worksheet, if at all you have put any statements/comments in the worksheet for your understanding, just disable those and then Ctrl+Enter starts working.
PS: I didn't do any other changes apart from this to make this shortcut work.
Cheers