eclipse で左右又は上下に２つ以上のソースコードを並べて表示する方法は次の通り。Eclipse allows split screen editing on multiple files but I believe you can't open the same file in two editors at the same time.
The split screen is achieved by the following:
1) Open multiple files (e.g. Controller.java, View.java and Model.java). They should now be stacked using tabs and the latest file, say Model.java, being "active".
2) Now left-click (don't release) on a "View.java"'s tab, drag the cursor to the lower edge of the active editor, wait a second so that the cursor changes into a black filled arrow, and release the mouse button. Voila, the two files (Model.java and View.java) should be now vertically split.
3) Now left-click (don't release) on "Controller.java" tab, drag the cursor to the right edge of one of the already open editors, wait a second so that the cursor changes into a black filled arrow, and release the mouse button. Voila, all three files are split into the screen.
http://www.coderanch.com/t/101996/vc/Split-screen-editor-Eclipse
タブ部分をドラッグして、下のほう又は右のほうに持っていけばいいのでした。
