[TreeBrowser] Open folder icon issue

[advice2020]

Linux
This can get tricky because it can be difficult comparing theme based items in Linux.

The TreeBrowser plugin by default uses 16x16 folder icons.
In my tests all the theme icon sets default folder icons work fine in this plugin.
However, I noticed that there may be an issue with the "opened folder" icons. They do not appear to be using the icons included in icon sets.

To hopefully limit the confusion we will use the very common "Papirus" icon set as example.
Use dark theme for DE.
Also we will use a dark theme for Geany, lets say something like "Spyder Dark".

For 16x16 Papirus uses a gray folder icon for regular folders and a flat gray horizontal icon for opened folders.
Can test this in file pickers or file managers, anything that allows you to see the folder icons in 16x16.

If you try this in TreeBrowser plugin, it always seems to be using the same open folder icon which looks like a white square icon in the background with a little white folder in the that squares lower right corner.

Would like to be able to use the open folder icons provided by icon sets.
Would anyone be able to take a look at the code and see if there is an issue?

Thank you to anyone who reads this

[advice2020]

QUESTION
While on the subject, I will probably keep the icon sizes as is, but does anyone know if there is a way to change the size of folder icons and also the MIME icons for actual file types?

Thank You

I'm not a Geany developer but I have experienced (from what I understand of the issue you reported) the same kind of oddities with icon themes. With specific themes (more exactly themes I created myself) I notice some icons that should be small (in the 16x16) become huge (i.e. more than 64x64). The opposite was also true: some icons that should be relatively large appeared as small as 16x16. If I remember correctly it occurred mostly in dialogue boxes and panels (Xfce panels that is).

Conversely, some applications or plugins do not react immediately to theme changes and I had to close my session and log back in. Pretty annoying at times.

So to my perception, this might have nothing to do with Geany but the icon theme you're using. If you change theme and peek at multiple ones, maybe you have the answer.

As for changing the icon picture for specific MIME types, the answer again belongs to the theme. Themes are not that straightforward under Linux — not that I recommend against twiddling, it just may take you a considerable amount of time to understand how it works and, most importantly, what icon file is associated with what...

[advice2020]

Thank you for your reply.
I think I mentioned that I tried a few different themes.
Yeah I had the same realization about the having to close and restart Geany to make sure theme changes applied.

I typed the following before reading above.

One of the purposes for this suggestion in general is that some icon themes use colored folders for folder icons.
When this is the case it can appear strange when folders are expanded and the folder icons become a completely different icon without the same color as the colored folder icon.
This makes them blend in and no longer look like folder icons with the other folders, makes it look more like a file MIME icon instead, which can look visually confusing.

So again would be nice if this could just use the "opened folder" icon used by theme.
Or if too complicated to achieve can just remove the "opened folder" icon and just use the regular folder icon for both collapsed and expanded folders.

Hopefully someone agrees / is willing to make this update.
Thank You