src/vs/workbench/browser/parts/editor/tabsTitleControl.ts/makeTabHoverBackgroundRule
		const makeTabHoverBackgroundRule = (color: Color, colorDrag: Color, hasFocus = false) => `
			.monaco-workbench .part.editor > .content:not(.dragged-over) .editor-group-container${hasFocus ? '.active' : ''} > .title .tabs-container > .tab.sizing-shrink:not(.dragged):not(.sticky-compact):hover > .tab-label > .monaco-icon-label-container::after {
				background: linear-gradient(to left, ${color}, transparent) !important;
			}

			.monaco-workbench .part.editor > .content.dragged-over .editor-group-container${hasFocus ? '.active' : ''} > .title .tabs-container > .tab.sizing-shrink:not(.dragged):not(.sticky-compact):hover > .tab-label > .monaco-icon-label-container::after {
				background: linear-gradient(to left, ${colorDrag}, transparent) !important;
			}
		`;