You may find certain limitations in creating new tabs on screens in SAP when working with "Create new tab". The list below is not a 100% complete list but it contains the most common issues.
We are not able to "fix" or workaround the issues as they are due to limitations in SAP.
The general rule when working with the system is that the "Left" value should never be bigger than the width of the screen when minimized. If you increase the "Left" value beyond the width some tabs will not be accessible.
Business Partner Master Data/Item Master Data
Issue: Changing the "Left" location of the tab may lead to making other tabs inaccessible.
A: You will need to have a lower left value than the width of the window. On the BP window SAP also shows/hides fields dynamically and this also leads to unpredictable behavior. The default "Left" value assigned when creating the tab is the left value we have found to work best.
My tab does not get "focus"
Issue: My tab does not get focused when clicked.
A: SAP has internal limitations in the number of Pane Levels (Pane Levels are what does the actual hide/show and are not 1 to 1 with tab numbers). If you reach more than 10 Pane Levels the tab will not get focused when clicked. The tab will still work but it will not change the look when clicked.