Firefox only does View Page Source , it doesn't have a "source" editor. You can easily set two hidden preferences to change that; one to tell Firefox to use an external editor, and the other to specify which editor to use.

http://kb.mozillazine.org/View_source.editor.external
http://kb.mozillazine.org/View_source.editor.path

Type about:config in the URL bar and hit Enter.
If you see the warning, you can confirm that you want to access that page.
Then edit those prefs.

No, that gives me code. I don't do code. The Netscape edit shows the page as it looks online but also shows boxes with text that I can then add to or delete. The solution provided needs 1. more skill than I have and 2. takes more time than I have. Cen

If you are referring to the old Netscape 7.* then that was a suite as it had a composer built it as it was based on the old Mozilla 1.7.* suite.

If you want a suite then look at SeaMonkey as it is a community effort to keep the old suite going strong. http://www.seamonkey-project.org/

Sorry, I never used Netscape so I am not familiar with that feature.

See if this extension meets your needs:
https://addons.mozilla.org/en-US/firefox/addon/browser-turns-editor/

Interesting extension.
I looked at the code and using this code with the Keyconfig extension should flip design mode on/off:

(function(){
var currVal=gBrowser.contentDocument.designMode;
if (currVal=='on') {
 gBrowser.contentDocument.designMode='off';
 gBrowser.selectedBrowser.setAttribute("showcaret","false");
}
else{
 gBrowser.contentDocument.designMode='on';
 gBrowser.selectedBrowser.setAttribute("showcaret","true");
}
})();

• http://kb.mozillazine.org/Keyconfig_extension
• http://dorando.emuverse.com/projects/mozilla/readme.html

This code will work in the Tools > Error Console if you paste it in the Code line and click Evaluate.

(function(){
var Cc = Components.classes, Ci = Components.interfaces;
var wm = Cc["@mozilla.org/appshell/window-mediator;1"].getService(Ci.nsIWindowMediator);
var gBrowser = wm.getMostRecentWindow("navigator:browser").gBrowser;

var currVal=gBrowser.contentDocument.designMode;
if (currVal=='on'){
 gBrowser.contentDocument.designMode='off';
 gBrowser.selectedBrowser.setAttribute("showcaret","false");
}
else{
 gBrowser.contentDocument.designMode='on';
 gBrowser.selectedBrowser.setAttribute("showcaret","true");
}})();