>Why my grids.columns.Width change on runtime
Plinio,
Might be you added code to init or if it's a subclassed grid, class might have the code. The most probable place is init but of course might be at somewhere else. For init, to see if it's the case, just temporarily comment existing code or if no code add a dummy line of code to suppress the class code.
Simple code that would change columnwidths :

this.columncount=-1
this.recordsource = this.recordsource

Cetin