from : http://bbs.ee.ntu.edu.tw/boards/Programming/10/2/13.html

發信人: [email protected] (葛瑞菲), 信區: programming標  題: Delphi 修改 VCL Source Code 需知發信站: 交大資工鳳凰城資訊站 (Tue Aug 29 15:51:19 1995)轉信站: cis_nctu!news.cis.nctu!news.csie.nctu!phoenix    Delphi 修改 VCL Source Code 需知(0) 備份欲修改部份之 Source Code 以防萬一.(1) 點選 Menu File|New Project 建立一個新的 Project(2) 點選 Menu File|Add File.. 載入欲修改的 VCL Sources Code        (3) 設定 Menu Options|Project 下列開關    (否則您的VCL .DCU Size比原本的大一倍都有可能....)    Project Options - Compiler    Dubugging Group         (1) Debug information Turn Off    (2) Local symbols Turn Off    (3) Symbol info Turn Off    Project Options - Linker    EXE and DLL options Group    (1) Optimize for size and load time Turn ON    (2) include TDW debug info Turn OFF         (4) 檢查 Unit 中是否已經 Uses 欲修改之 VCL Unit.(5) 以Project Manager再次檢查欲修改的 Source Code Unit是否已    加入 Project 中.加入Project後的Unit會被優先使用,而不再使用    原本\DELPHI\LIB同名的 DCU.(6) 修改完畢後點選Compile|Build All(7) 待完畢無誤後,Close Project.將新產生之 DCU 從 \DELPHI\SOURCE\VCL 搬至    \DELPHI\LIB(8) 點選 Option|Rebuild Library 重新產生 \DELPHI\BIN\COMPLIB.DCL.(9) 撰寫測試程式試之.

from: http://www.delphifaq.com/fq/q3056.shtml 

Cannot single step into VCL source code anymore

Question:
 
All of a sudden I cannot single step into the VCL source code anymore. The path to $(DELPHI)\Source\Vcl is in the Enviroment Options Direcotry and I also tried to add it to the Project Options > Debug Source Path but it did not help.
It appears that $(DELPHI)\ is correct since I added a absolute
path to the list and D5 reconized this was the $(DELPHI)\ path and
changed it back to $(DELPHI)\Source\Vcl automaticlly. What happened?
Answer:
Here are two possible reasons for your situation:
1) You may accidentally have unchecked 'Use Debug DCUs' in Project | Options Compiler. 

2) Perhaps you have switched 'Build with run-time packages' on. 

from: http://www.delphifaq.com/fq/q3061.shtml

 
Preventing the Debugger from stepping into VCL source
Does your debugger step into the VCL source code and you want to disable this?
Or are you in the opposite situation, you need to step into through the VCL source code?
Here are some pointers (for Delphi 5) what you should look at.
The following steps will stop the debugger from stepping into the VCL:
1) Go to menu 'Project | Options' and there click on tab 'Compiler'. Then uncheck the 'Use Debug DCUs' option under 'Debugging'. This is a project-specific setting.
2) Also check to be sure your Library path just points to LIB, not LIB\DEBUG. This is an environment option and will affect all projects.
3) Remove the VCL source directories from the Search Path. This is also a project specific setting. Choose under 'Project | Options' the tab 'Directories/Conditionals'. Delphi 5 allows to remove directories comfortably from the search path. The VCL source directories will look like
$(DELPHI)\Source\Vcl
There are problably be other directories below $(DELPHI)\Source, which you may want to remove as well. E.g. \RTL\
Happy Debugging!