You can actually make this work, but like the others, I don't recommend it.
To make your VI work. Right click on the "GO1" structure and select "Edit Events.....". At the bottom of the dialog, there is a checkbox that reads "Lock Front Panel until the event case for this event completes". With this checked, all front panel objects are locked until the GO1 event completes. This is what is causing the GO2 button not to work. Uncheck this and your application will work as you want it to.
If your intent is to have GO2 disabled until you click GO1, try the attached VI. It uses property nodes to disable the GO2 button until you click the GO1.
Another thing that you have setup that doesn't look necessary is the Timeout event, especially set to 1ms. The basic idea of the Event Structure is to not have to constantly poll for front panel events. If you just deleted the timeout event cases and removed the 1ms constant, your application would just well, but would just sit and wait for you to click a button.
Ed