On running the above code I find that button 5 is covered by button 4 and is not displayed at all. On investigating I find that if I remove mentioning gridwidth and gridheight then button 5 gets displayed.
Please help to understand how to get around this problem.
The soul is dyed the color of its thoughts. Think only on those things that are in line with your principles and can bear the light of day. The content of your character is your choice. Day by day, what you do is who you become. Your integrity is your destiny - it is the light that guides your way. - Heraclitus