Background: the monitor enduser used is larger than before, and the G/L screen (SAPLFSKB 0100) in Enjoy transaction codes like FB50/60/70 around 20%-30% of the area is free. And user hopes to be able to find all fields on the screen by restricting the required less fields using screen variants or transaction variant.
You can use the following way to change the frame of screen : SAPLFSKB 0100 for Enjoy transaction, but please be notice that these adjustments are modifications!
Let's take FB50 as an example:
1.Adjust width of overall frame and item frame for screen SAPMF05A/1001 (FB50/FV50), 1100 (FB60/FV60), 1200 (FB70/FV70).
Go to T-code SE51 to change the layout of SAPMF05A/1001 by pressing 'change' button
Drag the overall frame to the right 
then drag the item frame to the right, and press 'activate' and 'save' button
2.In SAPLFSKB screen/0100, same procedures like adjustment of SAPMF05A/1001 above, you can adjust the width of overall frame and table frame.
Go to SE51 enter SAPLFSKB and 0100, press change button, Drag the overall frame and then drag the item frame to the right and then press 'activate' and 'save' button.
3. Check the modified G/L sub-screen in FB50
Check SAP standard screen in FB50, after the comparing with the modified one above, you can see the screen of SAPLFSBK/0100 is enlarged.