How to stop VBA function showing formula result in Arguments Dialog in MS Excel -

when add udf ms-excel using vba, function gets evaluated twice when inserting:

1) arguments given function in function arguments dialog: hence result shown in function arguments dialog formula result

2) after clicking ok in function arguments dialog: hence result shown in respective cell.

i referred stop vba evaluate calling target function twice made function not evaluated ever.

can please know way of stopping double evaluation of udf function?

thanks

if problem of double evaluation speed considerations (the udf takes long time calculate) suggest following.

1. adding parameter called docalculate udf
2. put false in cell a1 in worksheet
3. point udf docalculate parameter cell a1
4. add line of code exit function if docalculate false

this way udf not calculate function dialog. activate udf changing a1 true