Editor: user actions in Project Explorer cause items & folders recreation, loss of folder states

[ivan-mogilko]

Describe the bug
Whenever you do (almost) any operation with items within a Project Explorer, such as moving items around, changing their names, adding and deleting items, and so forth, the Editor regenerates whole project subtree with items and folders. Not only this is an inefficient operation, but also it causes all folders to loose their collapsed/expanded state. This makes it very inconvenient for users to work with these folders, especially when they rearrange items.

AGS Version
Any version starting with 3.2.2 which introduced folders.

To Reproduce

1. Create several characters and several folders and subfolders.
2. Move one characters to any folder.
3. Move another character to any other folder.
4. Notice how the first folder has collapsed.

Expected behavior
Folders don't expand or collapse unless by user's direct command.

Cause and solution
The root of the problem is RePopulateTreeView method, which is sprinkled around all the Editor's Component classes. Whenever there's a change to a project item (added, deleted, moved, modified) this method is called, with the purpose of synchronizing project data and Explorer tree.
As mentioned above, this is very inefficient, and also is causing inconveniences.

The way I see this, the solution is to write another method for data->ui synchronization that would not blindly recreate whole tree structure, but do it more gracefully. For example, compare item by item and see which have changed. Alternatively, make this method accept a hint from the caller, which tells about recent changes.

[ericoporto]

there is an approach that is to save the state of everything and then reload it after repopulating. Example

The way I see this, the solution is to write another method for data->ui synchronization that would not blindly recreate whole tree structure, but do it more gracefully.

This could work too, we probably still would have places where a large change is applied so the repopulating would still be something to account, so maybe two solutions could be done.

[ivan-mogilko]

there is an approach that is to save the state of everything and then reload it after repopulating.

This is true, I mentioned this in the original forum thread, but forgot to mention here.
Although honestly I don't like recreating whole tree which may contain hundreds of items (in a big project) just if you edited an item's name or moved it to neighbour subfolder.

So, right, there may be both solutions in parallel.