You can reduce this delay. It is one of the simplest tweaks you can make to improve your experience in Windows.
In the Registry Editor:
Go to HKEY_CURRENT_USERControl Paneldesktop
Add a string value named MenuShowDelay if it doesn’t exist
Set it’s value with a smaller number (usually I would set it to 0), with a value specifying the number of miliseconds (400 is default, smaller numbers are faster).
Restart your machine