Attributes and formatting-signs in code for formulas is handled in a certain 
order. e.g. the * operation in normal algebra calculations has less 
priority than + operations. This holds true for attributes like vec or tilde.

But there are some inconvenient side effects:
vec a^2 (or vec a sup 2) places the vec-sign above a^2 and not only 
above a. so, it is always necessary to enter {vec a}^2.

Therefore, my enhancement request is to give vec-like attributes a 
lower priority, because the vec-decoration is normally only above a single 
variable - the current behavior could be archived with vec {a^2}

affected: vec, tilde, dot, ddot, ...