Legend entries trigger <Enter> and <Leave> events only on button click

[medranocalvo]

Reproduction steps:

% package require tkblt
3.2
% blt::graph .g
.g
% pack .g
% .g element create abc
abc
% .g legend bind abc <Enter> {puts Enter}
% .g legend bind abc <Leave> {puts Leave}
% .g legend bind abc <Button-1> {puts Button-1}
% # Hover the legend entry... nothing happens.
% # Click the legend entry:
% Leave
Enter
Button-1