Anyone knows how to turn off this blue hallow around buttons in ASSt, tried all sorts of button types etc., if I turn the button that’s got the blue, rebuild, the blue would come around another one on the interface…
I am not sure what you meant really but I am taking a wild shot.
Try to select your button in the IB and see your various settings for that button in the Attributes pane. You may have set something there that caused the blue hollow feature to show…e.g., border, enable, selected, etc. You may have to apply the tried-and-true “trial and error” method to see where the problem lies.
It sounds like you have full keyboard access on. This allows any control on screen to be focused on (selected), instead of just text fields and tables.
You can often tell what the current focus is on by the blue halo around that control.
To change it, go to System Preferences, open the Keyboard & Mouse pref pane, select the Keyboard Shortcuts tab, and fiddle with the settings at window bottom. As mentioned there, this setting can also be toggled using control-F7.