**System Information**
Operating system: Windows 10
Graphics card: Nvidia GTX 1070
**Blender Version**
Broken: 2.83-3.0
**Short description of error**
Over the course of two years that I have been using Blender on and off, I kept running into an issue where my custom hotkeys were removed from my keymap. This happened with hotkeys that I had been working with for months that worked perfectly fine (even just an hour ago at times). I have had dozens of instances where my custom hotkeys (but also those from the default keymap) were removed entirely without any other notable changes by me. Sometimes, they reverted back to the "factory reset" state, while I did not perform a factory reset. This is only for a few hotkeys at a time.
When creating a keymap entry within a custom keymap, these entries are propagated back to the default "Blender" and "Industry Compatible" keymaps. When switching keymaps, other hotkeys custom hotkeys are assigned to the other keymaps or default keymap items become associated to the custom keymap. It occored for instance, after checking for new hotkeys within the default keymaps (i.e. the 3.0 knife tool modal hotkeys).
**Exact steps for others to reproduce the error**
1. Go to Edit > preferences
2. Create a new keymap with the "+" button.
3. Right click preferences > Create keyboard shortcut
4. Type in "Ctrl+K"
5. Go back to Edit> preferences
6. When switching keymaps from the dropdown, notice that any of the assigned hotkeys in the custom keymap also exist within the default Blender & Industry compatible keymaps.
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7. Upon saving preferences for the custom keymap, the default ones remain affected.
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I suspect that, when switching keymaps (e.g. to check the default modal hotkeys for the new 3.0 Knife tool), default keys are put back into the custom keymap, thereby reverting some of the entries within a custom keymap. This is the reverse behaviour displayed in the videos above. Just like switching from the custom keymap to the default, adds custom keymaps to the default keymaps.
**Expectation**
I would expect that changing the keymap from the dropdown would load the other keymap and drop the changes made to the custom keymap (and prompt the user with a warning to save the current adjustments or to discard them). That way, if I migrate from a previous Blender version to the next, whilst retaining my custom keymap, I can look at the Blender/ Industry standard keymaps of the new version, which have all the new operators and modal keys assigned. That way, I would be able to copy/ paste them into my custom keymap and make sure it is up to date. Furthermore, I don't expect changes made to my own keymap to override the default Blender/ Industry standard, since the adjustments I made were made to my own custom keymap.
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//Some of the keymap items that were affected in the last day and a half, notice that all of these were set/ present in my previous install for over half a year ago//
```
**3D view - object mode**
A | To add objects in the 3d view > Reverted back to Shift + A
C+W, C+E, C+R (C associated to a modifier button) | Clear location, scale, rotation > reverted back to the defaults for these commands
Ctrl+1/2/3/4/5/6 | Subdivision set > all but Ctrl+1 was removed from the keymap
Ctrl+T | Apply transformation > removed
**2D view - Node editor**
Mousewheel Up/ Down | Zoom in/ out within the node editor > Reverted back to scrolling vertically
```