When selecting bones with the `Select All` hotkey, the `Select` option of all bones is disabled under certain conditions

[misaki-eymard]

Description: If you follow the specific procedure described below, when you press the Select All hotkey (by default ctrl+A), the Select option for all bones will be unchecked automatically, even if you haven't touched the Select option at all.

Expected behavior: The check status of the `Select' option will not change automatically if it is not changed by the user.

Steps to reproduce:

1. Download the attached .zip file: When selecting bones with the Select All hotkey, the Select option of all bones is disabled under certain conditions.zip
2. Open the Spine project that is inside the unzipped zip file in Spine 4.2.32.
3. Select bone1 and uncheck the Select option.
4. Select bone2 and bone3, and press the Select All hotkey (by default ctrl+A).
5. You can see that the Select checkboxes are unchecked for all bones.

The version of Spine in which this problem was found: Spine 4.2.32

This problem was reported in the following thread on the forum: https://esotericsoftware.com/forum/d/26395-bone-select-disappears

[NathanSweet]

This is by design. We don't currently have a way to show checkboxes and other UI controls as being in a "mixed" state.

The root bone has Select unchecked and the other bones are checked. After you select all, you have a selection containing the root bone and the other bones. Whenever multiple items are selected, if any are unchecked, then checkboxes are shown as unchecked. The individual items have not changed, they retain their checked or unchecked state until the checkbox is clicked.