Tiny bug in 2.7.0, to reproduce:
1) Bind Poke Tool to Ctrl+click;
2) Place a pin and any other component (for example, Adder) to the canvas;
3) Move the pin somewhere;
4) Empty selection;
5) Press Ctrl+click on the pin to change it's value;
6) Select other component (Adder), attribute table will be empty.