Maybe you simply want to fine-tune your forms to add your company logo, special instructions, or warnings for users.
Similarly do the same to validation controls and buttons in other tab. The reason which I think is creating problem for you is that you have validation controls in other tabs which fail when you click the button on the first tab though the validation controls in the first tab pass.
Combining parameters with a bitwise OR operator will result in a logical AND operation. Regardless of which parameters you specify for this method, a control must have its Control. Auto Validate property of the control or of the control's container to false if you want validation to happen only when you call Container Control.
You may use several Validation Constraints parameters at once by combining them with a bitwise OR operator. Validating event on controls that are both immediate children of the container AND are enabled.
Browsable(false)]public virtual Boolean Validate Children (Validation Constraints validation Constraints)Container Control.
Validating event occurs, it will cause the control to push its current data back to the data source.