Auto purchase required resources

i would like a feature that allows you to auto buy resources - if available in marketplace, when building troops or buildings - the amount of times i have gone to build only to realize am short on a resource - it already offers option to use gold to make up shortfall but would be super convenient if an icon was there to hit that would buy the shortfall from marketplace

this isnt so obvious when building one item troop or building but when selecting several provinces and multi buying its annoying that i need to close down go to marketplace buy odd 100 re then go back to finish production - as there is a link to purchase shortfall from gold why cant they use another icon to purchase that required from marketplace