As the title says...

When "Experimental Customization" is turned on, on iOS (my friend), the hotbar becomes unresponsive and blocks are placed (e.g. holding a bucket of water → water spills when trying to switch items...). Currently, if you tap it 10 times in a row, you can switch items, but it is nearly unusable... On Android (myself), the "..." button on the right side of the hotbar responds to green, but is unresponsive... As you can see in the screenshot, it is difficult to switch items... When my friend and I both turn off customization, it works normally (but is inconvenient). In 1.20.8, it was experimental but could be used normally, so I think the problem has occurred with the 1.21 update... Please fix it. (※Translation used)
※ In the previous version (1.20.8), the "Hotbar size (200%)" could be set, so it could be customized and used without any problems, but this was abolished in 1.21, so the affected versions are listed as 1.21 and onwards.

→※1. (980KB) Android (separate case) When editing custom buttons underwater, "the upper right (jump) button cannot be edited" (in the screenshot, a "□" is displayed in the sky even though it is not moving) / Addendum: When I edited it on a scaffold, the upper right button was edited normally. (However, all button sizes and positions that I set underwater were reset the moment I stepped on a scaffold.)

→2. (5.09MB) Android "..." not responding screen recorder (※I opened it the first time, but the second and third times, "..." is green, but I don't open it and use lava (item, block, etc.)...)