HI Kuan:
1. I noticed an issue with the IDE.
Selecting a block of code and then selecting CTRL + SHIFT + R (to un-comment the code) only un-comments code that has a comment character in the first column.
The code should un-comment any line that begins with the comment character in any column.
2. I think the search and replace is in dire need of upgrading. Right now I am reluctant to use it for anything but a search and replace of the entire file. It lacks information of what the selections do. For example the tool tip says "Scope" but I have no idea what scope when selected and what when not.
There is also no feedback as to whether anything was changed.
I also think it deserves its own window.
I recommend that you look at any text editor search and replace and shoot for that.
Here is a pic of the search window from Geany.
I don't think you need to go so far as to include reg. expressions or any other large coding task.
Basically what you have just reorganized a little.

3. Adding a new include file to a project forces you to use the .bi extension. That is not ideal. It would be better to allow .bas as well.
4. I wanted to add a text file to the project but I couldn't find a way. Is that possible? Not a big deal in any case.