Poor UX with ctrl-a : & disabling row-selection

[iplanwebsites]

Until block-copy of multiple selected cell is supported, I'd like to disable selection of rows. It's just confusing to my users.
They also use ctrl-a shortcut when focussed in a cell to select it's content, but it select the entire document.
Is there a way to disable row-selection?

[cscan]

A disable flag can be introduced. BTW, I am also thinking a way to auto-disable it when the editing is happening.