We have to add two more lines to the provided lines to prevent the display of these actions while submitting Budget Plans. The final lines would be as below:
a[href*='&object_code&ui.page.space=mainnav.work&populate_detail=Allocations&__isInstance=true'] {display: none}
a[href*='&object_code&ui.page.space=mainnav.work&populate_detail=Assignments&__isInstance=true'] {display: none}
a[href*='&object_code&ui.page.space=npt.projmgr&populate_detail=Allocations&__isInstance=true'] {display: none}
a[href*='&object_code&ui.page.space=npt.projmgr&populate_detail=Assignments&__isInstance=true'] {display: none}