If you are in creative mode and you have any tab open and your game mode changes during this, then after you start clicking on the inventory slots, items from the creativity tab that you were in earlier will start showing for a moment.

The bug is minor, but still a bug. Its essence is relatively simple. It consists in the fact that if you switch to creative mode and go to any tab and change your game mode without leaving the inventory and then start clicking on the inventory slots without leaving the inventory, then for a moment items from the creativity tab in which you were before changing your game mode will start to be shown. Learn more about how to reproduce this:

Switch to Creative mode by running the /gamemode creative command, or simply press the F3+F4 keys on your keyboard and select Creative mode.

Select any Creative tab such as Food and Drink and log in to it. Do not leave the inventory. After that, you need to change your game mode. You will not be able to use the /gamemode creative command or the keyboard shortcut F3+F4 to change the game mode, so in this situation on older versions you would have to use the command block and timer on repeaters or reproduce the bug on the local server in order to change the game mode from the second account to another excellent one. from Creativity. But on the latest version at the moment (26.1 Snapshot 10) You don't have to worry and just follow steps 1 and 2, and then just use the keyboard shortcut F3+N to change the game mode to Surveillance.

After that, just start clicking on all the slots in the inventory.

And you will see that after that, the inventory slots that you click on will start showing items from the Creativity tab that you were in before you changed the game mode to Observation. Additional information: I wrote “For a moment" just for the word since “an instant” is an inaccurate and approximate period of time. Most likely, items are shown in inventory slots for one clock cycle because in the fixed bugs MC-36696 and MC-73881, the problem was reproduced for exactly one clock cycle, so I assume that items are shown in inventory slots for exactly one clock cycle. Also, if you reproduce this bug on older versions, you will not be able to use the keyboard shortcut F3+N to change your game mode to Surveillance. As I described earlier (see step 3) You will have to use the command block and set a timer on repeaters, or open the world for a local network to log in from a second account and change the game mode to Observation. But of course on 26.1 Snapshot 10 you won't encounter a similar problem because You can simply use the keyboard shortcut F3+N to change the game mode to Surveillance. I don't know exactly which version of the game has this feature, but in principle it's not that important.