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Will open the helpful Delphi Find dialog box.
 

Will open the Find In Files dialog box, this is a very helpful search capable of finding text with a few very helpful options like:
Search All Files In Project, Search All Open Files and Search In Directories.
 

You should consider using replace whenever you need to replace many lines of code with another line of code or even just change a word. I started using replace with Turbo Pascal 7.1 and I think over all these years replace has saved me lots of typing. Sometimes simple things are very helpful.
 

Is very useful for an incremental searches, you will notice the words "Searching For:" in the Delphi Code Editor status line, after this just type in the word you are looking for, I use this often if I am working in a large unit, its very helpful.
 

Will open the Go To Line Number dialog box. 
Just type in the line number you want an it will appear in the Delphi Code Editor.
 

Will open the Find Error dialog box. Usefull to specify the address of the most recent runtime error.
 

Will open the Browse Symbol dialog box.