ISSUE 1 :
I always had an issue with the lack of an OK button to click in our KDM login screen. In fact if I remember correct, it was there in earlier releases, disappeared somewhere in-between, made an appearance again by itself or due to some forum posts, and then disappeared again. Right now, it is not there.
ISSUE 2 :
Try logging in using keyboard alone. If you have never done this before, then good. If not put yourself in the shoes of someone who does not yet know.
(This became apparent to me only when I had problems with the touchpad of my notebook not working)
My knowledge of keyboard only use in a GUI was that Tab is used to navigate between fields and ENTER to select the field/button. SPACE is used to fill checkboxes or put tick marks etc.
I have only root and a user configured. Initially when KDM presents itself, it shows the user login at the top and root at the bottom. The user name is slightly highlighted but not underlined.
Now this will make you think that the user is already selected. So if you try to enter a password, it will not accept. (probably because at this time your keystrokes are being used to locate the user name beginning with the letter typed. This will not be apparent in a login screen with only root and another user.)
OK. So now you will think that you should select a user first by hitting the tab may be. So you do that and the user name will be highlighted and underlined. Now you try to enter the password. Oh No. Bad password. (Very strange if you consider that there are only root and 1 user and the password is same for both!)
So I used the trick of plugging in external USB mouse and clicking on the user name and then entering password.
Now I am expecting to use the mouse. BUT only, there is no point to click. I have to hit ENTER to login.
EUREKA !!! After more than a month of fiddling and getting frustrated, today I landed the solution (the feeling was akin to arriving at E=MC^2.) I have to hit the Da*n SPACE BAR to select user.
So in all :
1. Arrive at the KDM LogIn screen.
2. Bring your hands to KEYBOARD.
3. Hit TAB.
4. Highlight user name.
5. Hit SPACE.
6. Enter password.
7. Hit ENTER.
Now I am sure many will laugh at me for not knowing this or that it is such a silly issue. But everyone has their own things that irritate and this has been mine for sometime now.
Just had a look at this http://docs.kde.org/stable/en/kde-workspace/kdm/configuring-kdm.html.
I did not see anything related to my issue there.