1641950 - Custom colors of folders not kept when folders are hidden

Status: RESOLVED DUPLICATE of bug 1637668

(Thunderbird :: Folder and Message Lists, defect)

Description

[Andreas]

User Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/83.0.4103.61 Safari/537.36 Edg/83.0.478.37

Steps to reproduce:

Change the color of a folder icon (right click -> properties -> icon color). Hide the folders by clicking the arrow symbol. Close Thunderbird and restart it.

Actual results:

When the folders are hidden, the custom colors aren't kept after restart. To keep the custom colors, the folder tree must be visible.

Expected results:

Remember the set colors even when the folders are hidden during Thunderbird start.

Comment 1

[Alessandro Castellani [:aleca]]

Thanks for reporting this issue.
I have a couple of solutions for this, but both might impact performance so we should be really careful which direction to go.

1. Apply custom colors to all the folders on startup, even those that are not visible.
2. Apply custom colors to subfolders only when the parent open state is toggled.

Solution 1. might not be optimal as we risk to go through hundreds of folders that are not even visible.
Solution 2. might cause some lagging in the UI if dealing with many subfolders.

Thoughts?

Comment 2

[Alessandro Castellani [:aleca]]

After experimenting with this, it's better to go with solution 1.
The fetching of colours happen in the background without affecting the startup speed or the UI.

With solution 2 instead, the slow down is fairly noticeable when opening a folder with many subfolders for the first time.
This will most likely be fixed in the improvements I'm adding in bug 1637668.