Capitalization
Title
Use for:
Actions in buttons, menus and tooltips
Headers in tables, popups, message boxes and dialogs
Headers of UI control groups
Do not use for:
Actions in links
Actions in the popup on Alt+Enter: quick-fixes, intention actions, and others
Headers in notifications
Rules
Always capitalize the first and the last words.
Capitalize the words in-between except:
articles: a, an, the,
coordinating conjunctions: and, or, but,
prepositions of four and fewer letters which are not a part of a phrasal verb: in, with.
In hyphenated phrases, capitalize all nouns, adjectives and adverbs: Auto-Indent, Command-Line Launcher. Do not capitalize articles, prepositions and conjunctions: Side-by-Side, Drag-and-Drop.
Examples
Compare With… — the short preposition with is capitalized as the last word.
Compare with Latest Repository Version — with is not capitalized when in the middle.
Check Out from Version Control — out is a part of the phrasal verb check out and is capitalized.
Sentence
Use for:
Labels of UI controls: text boxes, checkboxes, radio buttons, combo boxes, etc.
Items in combo boxes, lists, trees and tables
Links
Actions in the popup on Alt+Enter
Header and body text in notifications
Body text in error messages, tooltips, status descriptions and any kind of instructions
Rules
Capitalize the first word in a sentence, proper nouns and adjectives, and abbreviations.
Examples
Control+Shift+F — keyboard button names are considered proper nouns.
Accept the terms of the License Agreement — License Agreement is a proper noun.
Side-by-side layout — only the first word of a hyphenated phase is capitalized.