Account for half-scrolled lines in right-click

When a line is half-scrolled into view in the debugger, we need to take that
into account when calculating the line number that was targeted by a right-
click. This fixes the issue where the right-click targets always seemed slightly
off.

Fixes #417.

Java/Debugger/src/edu/umich/soar/debugger/helpers/FoldingText.java

@@ -979,16 +979,20 @@ public void expandPage(boolean state)
         setRedraw(true);
     }
 
-    // Returns the line we clicked on based on mouse coordinates
+    // Returns the line we clicked on based on text pane mouse Y position
     public int getLine(int mouseY)
     {
-        int topLine = m_Text.getTopIndex();
+        int verticalScrollOffset = m_Text.getTopPixel();
+        int adjustedMouseY = mouseY + verticalScrollOffset;
+
         int lineHeight = m_Text.getLineHeight();
-        int screenLine = mouseY / lineHeight;
-        int line = topLine + screenLine;
+        int line = adjustedMouseY / lineHeight;
 
-        if (line > m_Text.getLineCount())
+        if (line > m_Text.getLineCount()) {
+            System.err.println("WARNING: Right-clicked line number is greater than " +
+                "the number of lines in the text widget.");
             return -1;
+        }
 
         return line;
     }
@@ -1083,8 +1087,7 @@ public void makeCharPosVisible(int charPos)
      ********************************************************************************************/
     public int getCharacterPosition(String text, int mouseX)
     {
-        // The only way to compute this I can think of to compute which
-        // character was clicked on
+        // The only way to compute this I can think of
         // is to generate each substring in turn and check its length against
         // the point.
         // When we reach the correct length of string we've found the character.

Java/Debugger/src/edu/umich/soar/debugger/modules/FoldingTextView.java

@@ -751,11 +751,13 @@ public boolean find(String text, boolean searchDown, boolean matchCase,
     protected ParseSelectedText.SelectedObject getCurrentSelection(int mouseX,
                                                                    int mouseY)
     {
-        // Switchfrom screen coords to coords based on the text window
+        // Switch from screen coords to coords based on the text window
         Point pt = m_FoldingText.getTextWindow().toControl(mouseX, mouseY);
         mouseX = pt.x;
         mouseY = pt.y;
 
+//        System.out.println("Received right-click at (" + mouseX + "," + mouseY + ")");
+
         int line = m_FoldingText.getLine(mouseY);
         if (line == -1)
             return null;