Wondering why buttons appear/dissapper between Notes 5 client and Notes 4 client ... This is probably because the form has been edited using R5 sometime in the past.
As soon as a form or view is edited and saved using the R5 designer, a copy of the Action buttons is taken and stored in a field called $V5Actions whereas in R4 actions are stored in a field called $Actions. N.B.
There is probably a new design element for actions in R5 to cope with new shared actions. If you continue to make changes to the form in R5 no problem. Since any changes to actions in the R5 designer get written back to both the $Actions and $V5Actions field on the form design note. The problem arises if you then go back to making changes to the form in R4. Since the R4 client has no idea about $V5Actions any changes to buttons are only written to $Actions, which means that the two get out of step. This will result where it appears in the R5 client as if old buttons have suddenly appeared. This is because the V5 client only displays information from the $V5Actions field.
Solution: Create a new form or view using R4 and copy and paste all of the design elements from the damaged design element to the new one. Once done, delete the original design note and rename the new one.