Why does Slutsky compensation "overcompensate" the consumer? Suppose I have a Marshallian demand function $x_M(p_x^0,p_y,m^0)$. As I understand it, Slutsky compensation is defined as 

$$T_S = \Delta p_x \cdot x_M(p_x^0,p_y,m^0)$$

Can someone explain why this compensation overcompensates the consumer?
Here's a figure to explain:



Starting from the old price line, where the optimal consumption bundle is point $A$, we increase the price of $y$ to get the new price line.

The Slutsky compensation says that we have to give the consumer enough extra income so that he can afford to old bundle ($A$) at the new price. Thus, we shift the new budget constraint out to the dashed line.

The reason this "overcompensates" is that, taking the dashed line as the budget constraint, the consumer could afford bundle $B$, which gives him higher utility than he started with.