Perhaps I should have phrased my question differently:
No, I have to apologize: I did not look who submitted the post, I was convinced it was the author itself...
Because these items are missing, I cannot replace the standard status bar using Change Class.
When Lazarus tells you that the new class does not have all the properties of the old class, allow to delete these properties. Save the modified form and I'd recommend to exit and restart the IDE because a cached version of the unmodified unit would still be around and cause trouble. If Lazarus crashes when you allow to delete the properties, you still have the option to manually edit the lfm file (I know - normally I do not recommend to do this, but here you have no other choice):
- Close the IDE and make a backup copy of the form with the statusbar (both pas and lfm files), just in case...
- Open the pas file in an external editor, add "MyStatusbar" to the interface uses clause. Find the declaration of the statusbar (normally: Statusbar1: TStatusbar) - change this "TStatusbar" to "TMyStatusbar"
- Open the lfm file in an external ediitor. Find the block "object Statusbar1: TStatusbar". Replace "TStatusbar" by "TMyStatusbar" again. Remove the following (indented) lines (if available): "SimplePanel = ...", "SimpleText = ....", "ParentShowHint = ...", "ParentFont = ...". If you had to remove "SimplePanel" and/or "SimpleText" you must add code to your unit which adds a panel and writes the "SimpleText" to its Text property.
- Open the project (with the modified form files) into the IDE. Ideally it loads correctly, now with TMyStatusbar instead of TStatusbar. However, if there are more properties which TMyStatusbar does not implement, the IDE reports unknown properties again (ideally) or crashes. Kill the IDE. Load the lfm file into the external editor again and remove the reported missing properties.
Will TMyStatusBar be further developed by its owner, kefealo, and will the missing elements be added?
Only the owner knows... Let's hope that he did not disappear. If he did I could pick up his work, move it into my ExCtrls package and continue developing it myself - the author's license allows this.