TODO: Tab Bar Enhancements & Bug Fixes

[devvaannsh]

This issue is raised to keep track of all the things that needs to be done in the Tab bar

pending

• Dragging and dropping from one pane to another doesn't make it active. Eg: drag an active file a.html in pane 1 to pane 2 where b.html is active. expected a.html to be dropped and activated in pane 2, but b.html is still the active document, and a.html will be coming in the background tab only.
• Cannot drag and drop tabs over the editor in split pane. For eg. use vertical split, drag a tab from pane 1 and drop into the editor section in pane 2(not the tab header). the drop fails.
• Add Show Working set and Show File Tabs in the configure working set dropdown.
• A vertical bluish line appears when we drag a tab, that bluish line indicates where the tab will get dropped, but sometimes when for some reason the tab drop fails then at some cases the bluish line doesn't disappear. we need to make sure that the line disappears whether the drop fails or gets successfully executed.
• when we drop a tab to an empty pane we show a bluish border around it. a better approach would be to just highlight the editor like vscode does. also we need to highlight when user is trying to drop a tab in a non-empty pane too.
• sometimes when a tab is dropped from one pane to another, then (only sometimes not sure why and when) that tab is also shown as a placeholder tab from the pane where the drag started.
• all the icons in a tab i.e. the dirty icon, the directory name, the file name and the close icon are not properly aligned
• need to increase the z-index of the tab bar when a item from the menu bar is hovered then the background color that is shown obscure the tab bar active line marker. refer to the image below
  
• when tab is right clicked sometimes the editor's context menu with options like quick edit and all those open up. need to fix that
• Need to rename the button for close unmodified tabs because users might confuse with it that it will close unmodified git tabs which is not the case. it closes non-dirty tabs. Maybe also add option to close unmodified git tabs
  

integ tests

• Add Show Working set and Show File Tabs in the configure working set dropdown.
• Test cases for Tab bar

Core issues @abose

• In light theme, the tab bar file icons are not properly visible. fix: tab icon colors in light theme #2327
• tab bar sometimes disappears because of rendering issues. it gets hidden below the menu bar (tested in linux)
• Remove all the redundant title bars to save screen space.

[abose]

Done closing.
Titlebar wont be changed for now.