LicenseManager.UsageMode C #

I have a% base% base that everyone else inherits. I picked it up from a question here from the same site.

This is form :

public BaseForm()
{
    if (LicenseManager.UsageMode == LicenseUsageMode.Designtime) return;
    this.Load += BaseForm_Load;
    this.FormClosed += BaseForm_FormClosed;
}

I have already researched and did not clearly understand what the function of this part of the code is:

if (LicenseManager.UsageMode == LicenseUsageMode.Designtime) return