Distortation/flickering occur while Open one form & Close another in c#(Windows)

Distortation/flickering occur while Open one form & Close another in c#(Windows)

On some Event(e.g Button Click) on Form1

Form2 f=new Form2(ref newDataSet);

f.show();

Form1.close();

i'm also passing some DataSet,Variable to the constructor of Form2