I am trying to create two pop-up windows appearing one after another when my program starts. I used two button and single button dialog box. However, while the dialog box is active on the screen, I cannot modify the controls on my VI. Is there any way, I get modify the control while the dialog box is active? May be my approach is wrong, please direct to any relevant post/article on this topic.
Dialog boxes are modal. That means that they are in front of all other windows and no access to those other windows is possible until the modal window is closed.
If you cannot tolerate modal windows, then create your own dialog boxes using subVIs which open when called and then close afterwards. You can make them look like the modal boxes but they can be moved behind other windows. Of course they can also get lost back there. Keep that in mind if the response from those dialogs is required before some other part of the program can continue.