DragScroll (or Mouse Drag Scrolling) plugin enables scrolling of text areas such as the editor and the application / debug log by dragging the mouse Right or Middle key.
In an editor window, Mouse Drag Scrolling allows the user to drag (scroll) the text with the designated key (RightMouseDown or MiddleMouseDown).
Ctrl-MouseWheel zooming in the DragScroll plugin only applies to non-editor windows. It allows the user to zoom the other windows (StartHerePage, logs, Manager, Open Files List, etc).
DragScroll is contained in the plugin contribs folder of CodeBlocks.
See the CodeBlocks Editor Configuration settings to select the key and to adjust the speed and sensitivity.