me53n or me23n- Display issue

Hi everyone

i am a very new user to SAP.

When I am using me53n and i want to have a list of POs or PRs with some search criteria, I should click on the tab "Document View On" and then use the selection to get the results. My problem is that the left hand side pan is just 1 cm wide hiding the contents of "Document View On" and there is no cursor appearing to drag the dividing line to make it broader.

Can anyone please guide.