Sometimes I research some stuff in the research tree, spend too much and I'm unable to fill my abilities for the next battle.
This, from the point of view of user experience, is frustrating.

So, I propose a new option called "Auto Refill Abilities", with 3 possible settings:
Never
Ask First
Always

Always - after each game, calculate the cost of refilling abilities; if you can afford it, buy them, if not, display info box "Not enough resources to refill"
Ask First - after each game, calculate the cost of refilling abilities; if you can afford it, display the confirmation window with total cost of refill; if not, display info box "Not enough resources to refill"
Never - do nothing, equivalent of current version.