Change:
The grey used as the pinned tab separator could be a bit stronger and I suggest it is the same grey as for the View separators. !
Yeah, this color is pretty much randomly selected. would you be interested in picking colors for our default themes? Just today I pushed to add the color to our default themes but I did not really spend a lot of time thinking about which color fits best. Most often I picked the border color of the peek view inside the editor. The color key is
Are we sure we don't want to push this as a default for all themes? Because out of the box it's nearly impossible to tell the difference in other themes. Like below, can you tell which files are pinned? !
yeah if you can find a good base color and rule for it, I am all up for it

Discussion:
"tab.inactiveBackground": "#10192c", // "tab.activeForeground": "", // "tab.inactiveForeground": "", <del> "tab.lastPinnedBorder": "#596F99", </del> <ins> "tab.lastPinnedBorder": "#2b3c5d", </ins> // Workbench: Activity Bar "activityBar.background": "#051336",

"statusBarItem.remoteBackground": "#16825D", "sideBarSectionHeader.background": "#0000", "sideBarSectionHeader.border": "#61616130", <del> "tab.lastPinnedBorder": "#81818130", </del> <ins> "tab.lastPinnedBorder": "#61616130", </ins> "notebook.focusedCellBackground": "#c8ddf150", "notebook.cellBorderColor": "#dae3e9", "notebook.outputContainerBackgroundColor": "#c8ddf150"

"editorGroupHeader.tabsBackground": "#131510", "editorLineNumber.activeForeground": "#adadad", "tab.inactiveBackground": "#131510", <del> "tab.lastPinnedBorder": "#5e452b", </del> <ins> "tab.lastPinnedBorder": "#51412c", </ins> "titleBar.activeBackground": "#423523", "statusBar.background": "#423523", "statusBar.debuggingBackground": "#423523",

"tab.inactiveBackground": "#34352f", "tab.border": "#1e1f1c", "tab.inactiveForeground": "#ccccc7", // needs to be bright so it's readable when another editor group is focused <del> "tab.lastPinnedBorder": "#75715E", </del> <ins> "tab.lastPinnedBorder": "#414339", </ins> "widget.shadow": "#000000", "progressBar.background": "#75715E", "badge.background": "#75715E",

"peekViewResult.background": "#F2F8FC", "peekView.border": "#705697", "peekViewResult.matchHighlightBackground": "#93C6D6", <del> "tab.lastPinnedBorder": "#C9D0D988", </del> <ins> "tab.lastPinnedBorder": "#c9d0d9", </ins> "statusBar.background": "#705697", "statusBar.noFolderBackground": "#705697", "statusBar.debuggingBackground": "#705697",

// "tab.activeBackground": "", // "tab.activeForeground": "", // "tab.inactiveForeground": "", <del> "tab.lastPinnedBorder": "#EEE8D5", </del> <ins> "tab.lastPinnedBorder": "#FDF6E3", </ins> // Workbench: Activity Bar "activityBar.background": "#DDD6C1",

*--------------------------------------------------------------------------------------------*/ import * as nls from 'vs/nls'; <del> import { registerColor, editorBackground, contrastBorder, transparent, editorWidgetBackground, textLinkForeground, lighten, darken, focusBorder, activeContrastBorder, editorWidgetForeground, editorErrorForeground, editorWarningForeground, editorInfoForeground } from 'vs/platform/theme/common/colorRegistry'; </del> <ins> import { registerColor, editorBackground, contrastBorder, transparent, editorWidgetBackground, textLinkForeground, lighten, darken, focusBorder, activeContrastBorder, editorWidgetForeground, editorErrorForeground, editorWarningForeground, editorInfoForeground, treeIndentGuidesStroke } from 'vs/platform/theme/common/colorRegistry'; </ins> import { IColorTheme } from 'vs/platform/theme/common/themeService'; import { Color } from 'vs/base/common/color';

}, nls.localize('tabBorder', "Border to separate tabs from each other. Tabs are the containers for editors in the editor area. Multiple tabs can be opened in one editor group. There can be multiple editor groups.")); export const TAB_LAST_PINNED_BORDER = registerColor('tab.lastPinnedBorder', { <del> dark: null, light: null, </del> <ins> dark: treeIndentGuidesStroke, light: treeIndentGuidesStroke, </ins> hc: contrastBorder }, nls.localize('lastPinnedTabBorder', "Border to separate pinned tabs from other tabs. Tabs are the containers for editors in the editor area. Multiple tabs can be opened in one editor group. There can be multiple editor groups."));