IDE can't find lcl units ubuntu x64

[yanes19]

Hi all ,
I recently installed Lazrus from Ubuntu repos (Ubuntu 14.04 64 bit), and every thing goes fine
until I tested with a new blank project and it compiles fine also , but when I added a button and DblCkliked it
to go to the defaut event handler (OnClick) ,I got an error mssage :

Code: [Select]

The component editor of class "TDefaultComponentEditor" has created the error:
"Unable to find method. Please fix the error shown in the message window, which is normally below the source editor."

and the "Messages" window shows :

Code: [Select]

/usr/lib/lazarus/1.0.10/lcl/lclclasses.pp(32,10) Error: unit not found: Classes

I think it's  the same with SysUtils , and may be some other units .

How to solve this , please help !

[yanes19]

Ok , I think it's "partially" solved ,

I "backup-ed"  the folder .lazarus in my home directory and totally removed it , and then Got my Lazarus as when I installed it
Of course all my installed packages and my recent  stuffs has gone, but I reinstalled its and now every thing is working ,
This is not the best solution but , better than waiting and bothering the community with my questions 

[rvk]

Normally the "Tools" > "Rescan FPC Source Directory" works for me to resolve this issue.

It's also in the Wiki:
http://wiki.freepascal.org/Unit_not_found_-_How_to_find_units#Case_2:_Compiler_finds_a_unit.2C_but_IDE_does_not
http://wiki.lazarus.freepascal.org/Install_on_Ubuntu#Problem_2