Change:
With default Dark+ theme: !
Hi, I want to work on this, and I think is the file that needs to be changed, could you please advise on this? Thanks!

Discussion:
export const selectForeground = registerColor('dropdown.foreground', { dark: '#F0F0F0', light: null, hcDark: Color.white, hcLight: foreground }, nls.localize('dropdownForeground', "Dropdown foreground.")); export const selectBorder = registerColor('dropdown.border', { dark: selectBackground, light: '#CECECE', hcDark: contrastBorder, hcLight: contrastBorder }, nls.localize('dropdownBorder', "Dropdown border.")); <del> export const checkboxBackground = registerColor('checkbox.background', { dark: selectBackground, light: selectBackground, hcDark: selectBackground, hcLight: selectBackground }, nls.localize('checkbox.background', "Background color of checkbox widget.")); export const checkboxForeground = registerColor('checkbox.foreground', { dark: selectForeground, light: selectForeground, hcDark: selectForeground, hcLight: selectForeground }, nls.localize('checkbox.foreground', "Foreground color of checkbox widget.")); export const checkboxBorder = registerColor('checkbox.border', { dark: selectBorder, light: selectBorder, hcDark: selectBorder, hcLight: selectBorder }, nls.localize('checkbox.border', "Border color of checkbox widget.")); </del> export const buttonForeground = registerColor('button.foreground', { dark: Color.white, light: Color.white, hcDark: Color.white, hcLight: Color.white }, nls.localize('buttonForeground', "Button foreground color.")); export const buttonSeparator = registerColor('button.separator', { dark: transparent(buttonForeground, .4), light: transparent(buttonForeground, .4), hcDark: transparent(buttonForeground, .4), hcLight: transparent(buttonForeground, .4) }, nls.localize('buttonSeparator', "Button separator color.")); export const buttonBackground = registerColor('button.background', { dark: '#0E639C', light: '#007ACC', hcDark: null, hcLight: '#0F4A85' }, nls.localize('buttonBackground', "Button background color."));

export const listDeemphasizedForeground = registerColor('list.deemphasizedForeground', { dark: '#8C8C8C', light: '#8E8E90', hcDark: '#A7A8A9', hcLight: '#666666' }, nls.localize('listDeemphasizedForeground', "List/Tree foreground color for items that are deemphasized. ")); /** <ins> * Checkboxes */ export const checkboxBackground = registerColor('checkbox.background', { dark: selectBackground, light: selectBackground, hcDark: selectBackground, hcLight: selectBackground }, nls.localize('checkbox.background', "Background color of checkbox widget.")); export const checkboxSelectBackground = registerColor('checkbox.selectBackground', { dark: editorWidgetBackground, light: editorWidgetBackground, hcDark: editorWidgetBackground, hcLight: editorWidgetBackground }, nls.localize('checkbox.select.background', "Background color of checkbox widget when the element it's in is selected.")); export const checkboxForeground = registerColor('checkbox.foreground', { dark: selectForeground, light: selectForeground, hcDark: selectForeground, hcLight: selectForeground }, nls.localize('checkbox.foreground', "Foreground color of checkbox widget.")); export const checkboxBorder = registerColor('checkbox.border', { dark: selectBorder, light: selectBorder, hcDark: selectBorder, hcLight: selectBorder }, nls.localize('checkbox.border', "Border color of checkbox widget.")); export const checkboxSelectBorder = registerColor('checkbox.selectBorder', { dark: editorWidgetBackground, light: editorWidgetBackground, hcDark: editorWidgetBackground, hcLight: editorWidgetBackground }, nls.localize('checkbox.select.border', "Border color of checkbox widget when the element it's in is selected.")); /** </ins> * Quick pick widget (dependent on List and tree colors) */ export const _deprecatedQuickInputListFocusBackground = registerColor('quickInput.list.focusBackground', { dark: null, light: null, hcDark: null, hcLight: null }, '', undefined, nls.localize('quickInput.list.focusBackground deprecation', "Please use quickInputList.focusBackground instead"));

padding-left: 3px; } <ins> .customview-tree .monaco-list .monaco-list-row.selected .custom-view-tree-node-item .custom-view-tree-node-item-checkbox { background-color: var(--vscode-checkbox-selectBackground); border: 1px solid var(--vscode-checkbox-selectBorder); } </ins> .customview-tree .monaco-list .monaco-list-row .custom-view-tree-node-item .custom-view-tree-node-item-checkbox { width: 16px; height: 16px;