visualizations

Add xpack.apm.ui.transactionGroupBucketSize to cloud allow list.

It'd be great to be able to load an external history upon initializing the undo/redo feature.

It's already supported by the Undoo lib, through the import(history) API, so it should be trivial to implement.
https://github.com/fabioricali/undoo#undooimporthistory--undoo

I suppose changing the UndoProps by adding a initialHistory prop would do the trick:

export interface UndoPr

Describe the bug
If a heatmap is configured to fill it's container element completely, changing the container size (e.g. by resizing the browser window), will change the size of the visible chart, but scrollbars will appear and the user can scroll into whitespace of the original size.

To Reproduce
Steps to reproduce the behavior:

1. Go to https://codesandbox.io/s/polished-snowflake-v

Splash screen right now is inconsistent with the theme, it would be better to have a theme based splash screen for both iOS and Android implemented in flutter itself.

Is your feature request related to a problem? Please describe.
In a few places we're forcing a disabled element by adding the class

.navi-report__action-link--force-disabled {
  color: @disabled-gray !important;
  cursor: not-allowed !important;
}

Probably because some child's cursor and color styles ignore its parent's disabled attribute/class.

**Describe the solution y