I have a Visualforce tab, in which
showHeader = false. In classic it is working fine. But when this Visualforce tab is getting clicked in lightning, the Visualforce page opens with the search bar and header tabs. How to hide these tabs and search bar?
Good question. From the documentation https://developer.salesforce.com/docs/atlas.en-us.pages.meta/pages/pages_compref_page.htm:
A Boolean value that specifies whether the Salesforce tab header is included in the page. If true, the tab header is displayed. If not specified, this value defaults to true. Note: In Lightning Experience and the Salesforce app the value of this attribute is overridden, and is always false.
HOWEVER: You can see that it is actually TRUE in Lightning Experience. As you will learn in the Trailhead module, that header cannot be removed in LEX.
For more information, try the Trailhead module Visualforce & Lightning Experience https://trailhead.salesforce.com/en/content/learn/modules/lex_dev_visualforce