why no "Hold Fire" button

[schnorchel]

Thank you very much Sneaksie!

But I found one thing, the tank unit still moves to the close target without given order even if this hold fire button is toggled. sometime this is a suicide because they will expose their side to the long range enemy(AT gun for example). this is really annoying.

[Sneaksie]

Hold fire is not equal to hold position. You can order unit(s) to hold position by left-clicking the movement mode button (it functions much like the fire mode button you are already familiar with). Look through 'Orders' chapter in the game manual, it may clear up some not obvious features for you.