Useful to know

To make only contacts of a particular protocol appear in the contact list, you need to click on the desired protocol icon in the status bar of contact list with the LMB while holding down Ctrl.
To return to usual view mode, click LMB on an empty space between protocol icons.

If you start typing in the wrong keyboard layout:

You can change the layout of typed text with the key combination Ctrl + R.
Press Ctrl + Y to change the case of typed text.
Press Ctrl + T to transliterate the text.
Holding Alt instead of Ctrl makes all those operations applied only to the last word.

Note: Requires plugin Keyboard layout.

You can quickly send a screenshot of your desktop to your contact. To do this, press Print Screen (or PrtScr ⎙), put the cursor in the text field and press Ctrl + V. This will open a file transfer window with the screenshot ready to be sent to your buddy.

A tooltip appears when you hover the mouse over a contact. You can easily copy any data from it by pressing the Ctrl + C and choosing an item.
Note: Requires plugin Tipper.

You can switch between tabs by moving the mouse over them and twisting SW. You can also drag and drop tabs with Ctrl + LMB and Alt + LMB. If Ctrl is used, Miranda will remember the location of the tab and will always restore its position. Clicking on the tab with the MMB closes it.

Clicking with LMB on the contact's client icon in the contact list opens user details for this contact.

Clicking Ctrl + RMB on the contact in the contact list makes items related to Authorization appear in the context menu even for authorized contacts.
Note: Could be useful if you have problems with authorization.

Click LMB in a free area of the contact list and start typing (contact's Nick or Name) to search for the contact with highlighting the search results.
Press Esc to return to usual view mode.

To quickly delete or move a large number of contacts to other group, you need to call the module "Quick search" by pressing Alt + F3 (or Main menu → Settings → Quick search). You can select contacts using LMB and buttons Ctrl and ⇧ Shift there.
Note: Requires plugin Quick search.

You can add contacts to the list without Internet connection. Open Find/add contacts window, enter the ID of the desired contact and press Search button while holding Ctrl. The contact should appear and you will be able to add it in usual way.
Note: Works only with ICQ protocol.

If "IEView" is used as global message log display, the font size in messaging dialog can be changed by + and − buttons in the top right corner of the window.
If "TabSRMM internal log" is used as global message log display, the font size in messaging dialog can be changed by twisting the SW while holding Ctrl.
If "History++" is used as global message log display, the font size in messaging dialog can be changed only through Settings → Customize → Fonts and colors → History++.

LMB — Left mouse button

MMB — Middle mouse button

RMB — Right mouse button

SW — Scroll wheel