Which character(s)?

@Karl
Now all characters..No character's unicode is being displayed. If i put it in names mode, the name of the glyph is appearing on the glyph cell , but if i am using unicode mode nothing is happening. Also after opening the glyph in its own window, when i right click and go to properties, the name field displays the name but the unicode field is blank for all the glyphs. I tried to assign it unicode by clicking the emerald colored diamond shaped icon but nothing happened.

But it would be good to know which characters this is happening with, for example could you show the behaviour of the lower-case A (0061)? In your screen grab none of the characters displayed have glyphs in them and so it is difficult to get a feel for which encoding set-up and what characters you are working with.

I had changed the encoding to default encoding and i am getting UNICODE names for the characters i made already but not for the ones i have not touched. Attached picture might give you a better idea
Picture: http://postimage.org/image/6073j4gb5/

I think i had solved it. I changed the encoding to default and also when i quadruple click on a glyph cell, the Unicode number appears. So i guess that settles the problem.

Why are you worried about Unicode not displaying in blank glyph windows? (as shown in your pic)

Just thought it was an issue but i figured it out that it was not :) Newbie troubles that's all

Glyph names are mapped to Unicode values using the .nam files stored in the FontLan/Shared/Mapping folder. By default, FontLab's 'Standard Table' is used, which is based on the Adobe Glyph List and uniXXXX algorithm. It is possible to create custom .nam files, which are helpful if you want to employ custom mnemonic names during development instead of uniXXXX names for scripts not covered in the Adobe list. If Unicodes are not being automatically assigned to newly created glyphs, it is an indicator that there is a mismatch between the current .nam file being referenced by FontLab and the glyph names you are using. Select 'Generate Unicode' from the Glyph\Glyph Names menu to activate an appropriate .nam file.

[Note that if using custom .nam files, every once in a while FontLab will revert to is Standard Table. I've never figured out what triggers this.]