Key combination only triggering once

[Peytoncl]

            var screenshotBind = Combination.FromString("Shift+Control+A");
            Action screenshotAction = TakeScreenshot;

            var assignment = new Dictionary<Combination, Action>
            {
                    {screenshotBind, screenshotAction}
            };

            Hook.GlobalEvents().OnCombination(assignment);
            Hook.GlobalEvents().MouseDownExt += MouseDown1;
            Hook.GlobalEvents().MouseUpExt += MouseUp1;

the key combination triggers once and wont run the action after that.