Why it is not move my blue dot

Question

https://code.sololearn.com/Wy3IGbhE0EOc/?ref=app

Answer 1

You need to draw your rect again with updated value and remove old one

I dont know very well canvas, so old rect have some border :D

Best is to make some draw function, to dont repeat same code.
Set parameters to take color, and you can have both draw and delete old in one code.
https://code.sololearn.com/Wx8Illqc150O/?ref=app

Answer 2

Ty man