Hi team,

Indeed, there is an accessibility bug in Splitter. It is known. Thus, I'm marking this item as a duplicate of the original one: Splitter splitbar and resizer are not visible in high contrast mode. I'm sorry that it caused you trouble.

The Splitter resizers use a background color, which is removed by High Contrast mode. You can use borders as a workaround:

<style>
    .k-splitter .k-splitbar,
    /* and/or */
    .k-splitter .k-resize-handle {
        border: 1px solid;
    }
</style>

You can also:

• apply the above style only when high contrast is enabled
• set a border color, which matches your theme, so that the border is not visible in non-high-contrast mode

Regards,
Hristian Stefanov
Progress Telerik