When you select a sub-menu from within a drop-down menu in Photoshop, the sub-menu initially points to the right hand side but displays on the left hand side.
This issue has been reported on systems running Windows.
Solution
To resolve this issue:
Open the Run dialog in your system by pressing the Window key+R.
Copy and paste the following text in the Open section:
shell:::{80F3F1D5-FECA-45F3-BC32-752C152E456E}
Click OK.
The Tablet PC Settings dialog is displayed. Click the Other tab.
Select Other tab
In the Handedness section, select Left-handed. This allows menus to appear to the right side of your hand.